Sen. Marco Rubio's political action committee is going up with a TV ad defending New Hampshire Sen. Kelly Ayotte's votes on gun control.

"Safety, security, family - no one understands these things like a mom, and no one works harder for them than this one," the ad says, showing a photo of Ayotte. "A former prosecutor, Kelly Ayotte knows how to reduce gun violence."

The ad, being run by Reclaim America PAC, represents the first time the PAC has gone on air for a specific candidate. Reclaim will spend six figures on the ad, a source familiar with the buy said, in New Hampshire markets. The ad will start airing on Tuesday.

Ayotte, who is not up for reelection until 2016, has been the focus of gun-control advocates after she voted against the compromise bill on stricter background checks proposed by Sens. Joe Manchin (D-WV) and Pat Toomey (R-PA) last month. Ayotte got into a back-and-forth with a Newtown family member victim at a town hall earlier this month during a congressional recess in New Hampshire.

A Dartmouth poll out Monday showed Ayotte's favorability rating slipping in the Granite State, a place Barack Obama won twice. Ayotte's negative rating ticked up seven points in the poll, going from 36 percent favorable, 24 percent negative before the gun debate to 37 percent positive, 31 percent negative afterward.

This story was originally published on Mon May 13, 2013 1:27 PM EDT

New York City Mayor Michael Bloomberg has a promise -- or a threat -- for congressional candidates: In advocating more gun control, he'll put his money where his mouth is. 

Just ask the House hopeful who faced over $2.2 million Bloomberg-funded ads -- or talk to the Democrats charged with trying to take back the House majority in 2014. 

The billionaire mayor spent the money attacking former Rep. Debbie Halvorson, a Democrat who had been favored to win a Chicago-area House seat, over her "A" rating from the National Rifle Association. On Tuesday, 75 days after 20 children and 6 adults were massacred at Sandy Hook Elementary in Newtown, she lost decisively to former state Rep. Robin Kelly in the Democratic primary for disgraced Rep. Jesse Jackson Jr.'s seat in Illinois' second congressional district. 

"This is an important victory for common sense leadership on gun violence, a problem that plagues the whole nation,” Bloomberg said in a Tuesday night statement -- commenting on a special election primary in a district nearly 800 miles from his home. As she conceded, Halvorson blamed Bloomberg's money for her failed campaign. 

Her loss is one of the first real data points to dot the political landscape facing President Barack Obama -- and the Democrats he'll need to stand with him -- as he pushes a package of new gun control laws in the wake of the Newtown shootings. The president wants to ban assault weapons like the gun used at Newtown, limit the number of rounds of ammunition in magazines, require universal background checks for gun buyers and make gun trafficking a federal crime. 

It would be all but impossible for an assault weapons ban to pass the Senate — and prospects for any new laws are even dimmer in the GOP-controlled House. But lawmakers from both parties say could support requiring anyone who buys a gun to get a criminal background check. Under current law, people who buy guns from private sellers aren't required to get that check. 

So why does Halvorson's race matter to the legislative and political fights? After all, skeptics note, gun control isn't a controversial issue in urban Chicago, a city plagued by gun violence and a high murder rate. Bloomberg's tactics would likely be much less effective in a rural swing district with an ingrained hunting culture.    

But going after every pro-gun Democrat isn't quite the point, advocates say. Instead, it's a way of reassuring lawmakers -- particularly in swing suburban areas -- that someone will have their back if they support new gun restrictions.  

And it's also about telling Republicans in similar situations -- like those who hail from suburban Philadelphia, New York and Denver -- that there's a new threat. 

"The NRA has been the only game in town. That's not going to be the way it is anymore, and races like Halvorson's...are intended to send that message," said Mark Glaze, executive director of Mayors Against Illegal Guns, the advocacy group that Bloomberg co-chairs. 

In the past, the NRA has aggressively targeted lawmakers who back new gun laws. After a Democratic Congress passed an assault weapons ban in 1994, Republicans swept back to power in the House. The ban was allowed to expire in 2004. This time around, the NRA is opposing universal background checks.

Now, though, Democrats insist Bloomberg's millions amplify a new reality: changing public attitudes in the wake of Newtown. Polls show support for new gun restrictions is higher than it's been in more than a decade. And gun control advocates have retooled their message, focusing on reducing gun violence instead of trying to litigate Second Amendment rights. It's a distinction some Democrats believe will help turn the tide on an issue they've historically struggled with -- one strategist compared it to focusing on raising taxes on the rich during the 2012 campaign, helping their party win on the broader tax issue, where Republicans had previously claimed the upper hand. 

There's already evidence that suburban Republicans are staking out support for some new gun laws -- a reality that GOP strategists were eager to point out.  

"I think the idea of background checks across the board, I'm not opposed to them," Rep. Joe Heck, R-Nev., told the Las Vegas Review Journal's editorial board. "I disagree with people who say that this is going to be the first step to gun registration, which leads to gun confiscation."

"I agree with the president that we can and should strengthen the nation's background-check system," Rep. Pat Meehan, R-Pa., said in January. Also supporting stronger checks is fellow Philadelphia-area Republican Rep. Mike Fitzpatrick.  

After Newtown, polls show support for stricter gun laws is increasing even among Republicans. A new NBC News/Wall Street Journal poll out Tuesday showed 61 percent of Americans think gun laws should be more strict, the highest percentage since 2000, after the Columbine shootings months earlier. That's up from 51 percent in January of 2011, the last time the poll question was asked prior to Newtown. The shift is largely due to Obama's coalition of Democrats, African Americans and Hispanics. But among Republicans, 37 percent now say gun laws should be stricter. Just 24 percent of Republicans said so in January 2011. 

Obama and Democrats want to act fast on gun measures to maintain that momentum. In the Senate, Judiciary Committee Chairman Patrick Leahy wants to start the process of writing new gun laws on Thursday. Republicans could push that another week. 

In advance of the hearings, Democrats are scrambling to hash out a deal with Sen. Tom Coburn, R-Okla, on a background check bill. Coburn has been negotiating with Democrats for weeks, but talks have stalled in recent days over how to keep track of private gun sales so police can later track guns used in crimes. Democrats and gun control advocates say gun sellers need to keep a record or the law will be toothless, while Republicans argue that could lead to the federal government tracking gun owners. 

"There absolutely will not be record keeping on legitimate, law-abiding gun owners in this country," Coburn said on "Fox News Sunday."  

The slowed negotiations with Coburn have prompted Democrats, led by West Virginia Sen. Joe Manchin, to ratchet up what's been ongoing outreach to other moderate Republicans who might be willing to sign on. Sen. John McCain said Wednesday that he's been involved in working on legislation.   

Leahy's committee is also going to take up the likely doomed assault weapons ban, which California Sen. Dianne Feinstein is sponsoring. Democratic leaders have pledged a floor vote on the measure -- a move Obama urged at his State of the Union address, when supporters in the chamber erupted into chants of, "vote, vote, vote." 

Holding the vote is a significant part of the political calculus: It would allow Democrats in red states or swing districts to say they've opposed Obama's plan to ban weapons while still giving them an opportunity to tout support for other measures to reduce gun violence. 

"I want it on the floor," Feinstein told NBC News on Tuesday. 

NBC's Domenico Montanaro and Carrie Dann contributed to this report. 

UPDATED, 12:34 pm ET -- Nebraska Republican Sen. Mike Johanns will retire at the end of his current Senate term.

"We have decided not to seek re-election," Johanns and his wife, Stephanie, wrote to constituents Monday. "It is time to close this chapter of our lives." 

Johanns called state Republican officials, including Nebraska Gov. Dave Heineman, to inform them of his decision to retire. Heineman is likely to seek Johanns' seat, open in 2014. 

An announcement event wasn't planned, but the senator had already scheduled a series of town hall meetings across his state this week while the Senate is on break.

Johanns is one of just two Republican senators publicly backing former Nebraska Sen. Chuck Hagel's (R) nomination to be defense secretary. Other GOP senators have been aggressively critical of their former colleague, labeling him unqualified for the job. Hagel's nomination by President Obama was filibustered this past week as GOP opposition to Hagel intensified. Johanns replaced Hagel in the Senate.

Before he was senator, Johanns served as governor of Nebraska and was Secretary of Agriculture under former President George W. Bush. 

Several candidates have already told state Republican officials they're interested in running. Heineman can't run for the governorship again -- he's term-limited -- and will be ending his tenure as governor in 2014, making the timing of the race ideal. 

Also interested is Jon Bruning, the current attorney general, who lost to current Republican Sen. Deb Fischer in the Senate primary in 2012. State treasurer Don Stenberg, who's run for Senate four times before, could also get in, as could U.S. Rep. Jeff Fortenberry.

Here's Johanns' full letter to constituents:

Dear Fellow Nebraskans,
    We would like to share with you a decision we have made about running for re-election to the United States Senate. We have decided not to seek re-election.
    Words are inadequate to fully express our appreciation for the friendship and support you have given to us over the past three decades.
    With everything in life, there is a time and a season. At the end of this term, we will have been in public service over 32 years. Between the two of us, we have been on the ballot for primary and general elections 16 times and we have served in eight offices. It is time to close this chapter of our lives.
    During these many years, we have cherished our time together. So as we think about the next stage of our lives, we want a quieter time with our focus on each other, our family and our faith. We are also confident that there will be many more opportunities to serve our state and our nation.
    We look forward to the remaining time in the Senate. It is an honor to have served in so many ways over so many years.
    May God continue to bless Nebraska and our great nation.
                        Sincerely, Mike & Stephanie Johanns 

This story was originally published on Mon Feb 18, 2013 11:35 AM EST

Former Sen. Chuck Hagel (R-NE) met with Appropriations Committee Chairwoman Barbara Mikulski (D-Md.) on Capitol Hill Thursday. The two met in original Appropriations Committee hearing room in the Capitol.

A Democratic aide said Mikulski, as Appropriations chair, planned to discuss the looming sequester with Hagel.

The two took no questions during a brief photo opp. Hagel declined to answer questions about whether he would release additional documents to the Armed Services Committee, as Republicans are requesting.

A vote in the committee on his nomination, originally planned for today, was delayed, as Republicans are asking for more about his financials and speeches.

Vice President Joe Biden acknowledged that new gun laws would not "fundamentally alter" the likelihood of another mass shooting, though he insisted there has been a "sea change" in American views on guns in the wake of Newtown.

"Nothing we're going to do is going to fundamentally alter or eliminate the possibility of another mass shooting or guarantee that we will bring gun deaths down to 1,000 a year from what it is now," Biden told reporters Thursday afternoon after he spent over an hour lunching with Democratic senators at the Capitol.

"But there are things that we can do, demonstrably can do, that have virtually zero impact on your Second Amendment right to own a weapon for both self defense and recreation that can save some lives," he said.

Biden was on the Hill to help sell a package of changes to the nation's gun laws that President Barack Obama is pushing in the wake of the Newtown, Conn., shootings that killed 20 elementary school children and six adults. The president wants an assault weapons ban, limits on the size of gun magazines, universal background checks and a federal gun trafficking statute.

The 1994 assault-weapons ban was allowed to expire in 2004, and there had been little appetite to reenact it.

Still, that was before Newtown -- and the vice president insisted Thursday that the tragedy there changed the public's attitudes toward gun-safety legislation, a reality that would make new firearms regulations possible.

"I'm not saying there's an absolute consensus on all these things," Biden said, "but there is a sea change, a sea change in the attitudes of the American people. I believe the American people will not understand -- and I know that everyone in that caucus understands -- they won't understand if we don't act.

"The visual image of those 20 innocent children being riddled with bullets has, has absolutely, not only traumatized the nation, but it has caused-- like the straw that broke the camel's back."

As evidence, he pointed to what he said was new support from evangelical Christian groups for some gun regulation. Biden told reporters that support from conservative religious groups that represent largely rural constituencies was different than it's been during past legislative fights over guns.

Biden said he did not watch a gun violence hearing the Senate Judiciary Committee held Thursday; at that hearing, Democrats and gun-violence victims clashed with Republicans and the National Rifle Association over whether universal background checks would reduce gun crimes.

Biden on Wednesday met with former Rep. Gabrielle Giffords and her husband, Mark Kelly, who both testified at the Senate hearing.