After weeks of furious attacks on the campaign trail, as well as millions of dollars in hard-hitting television ads, the increasingly negative tone of the election has taken a toll on President Barack Obama and Republican Mitt Romney, according to the new NBC News/Wall Street Journal poll.

Both presidential candidates have seen their “very negative” ratings increase to all-time highs in the poll. And Romney’s overall favorable/unfavorable score remains a net negative – a trait no other modern presumptive GOP presidential nominee (whether Bob Dole, George W. Bush or John McCain) has shared.

What’s more, pluralities say that what they’ve seen, heard and read about the two candidates in recent weeks has given them less favorable impressions of each man.

Indeed, the percentages signaling a less favorable impression about these candidates – especially at this point in the race – are greater than what the NBC/WSJ poll showed in the 2004 and 2008 presidential contests.

“This is not characteristic … for July,” says Republican pollster Bill McInturff, who conducted this survey with Democratic pollster Peter D. Hart. “These are numbers you usually see in October.”

“It does speak to the growing polarization of the campaign,” McInturff adds.

A composite image of President Barack Obama, left, and Republican presidential candidate Mitt Romney. Photos taken July 24, 2012.

The horserace remains tight
In the presidential horserace, Obama leads Romney by six percentage points among registered voters, 49 percent to 43 percent.

That’s a slight change – within the margin of error – from last month’s poll, which showed Obama ahead by three points, 47 percent to 44 percent.

Read the full poll here (.pdf)

In a smaller sample of registered voters living in 12 battleground states (Colorado, Florida, Iowa, Michigan, Nevada, New Hampshire, New Mexico, North Carolina, Ohio, Pennsylvania, Virginia and Wisconsin), the incumbent president’s lead over Romney is eight points, 49 to 41, which is essentially unchanged from June.

But among high-interest voters across the country – those indicating a “9” or “10” in interest on a 10-point scale – Romney edges Obama by two points, 48 percent to 46 percent.

What remains remarkable about this presidential contest, according to the NBC/WSJ pollsters, is how stable it has been, despite everything that has occurred in the past month.

For example: The U.S. Supreme Court decision upholding Obama’s health care overhaul; the June jobs report, which showed that just 80,000 jobs were created last month; and the daily campaign attacks and counterattacks (including snipes over Obama’s business views, Romney’s unreleased tax returns, and the Republican’s time at Bain Capital).

“So much has happened, and so little has changed,” says Hart, the Democratic pollster.

Negative views on the rise
But what did change was an increase in negative views about both Obama and Romney. The president’s favorable/unfavorable score in the poll is 49 percent to 43 percent, a slight change from June when it was 47 percent to 38 percent.

Moreover, 33 percent view Obama very positively, while 32 percent view him very negatively – which is his highest “very negative” number in poll.

By comparison, Romney’s overall favorable/unfavorable score is 35 percent to 40 percent, with 24 percent viewing him “very” negatively – also his highest mark here.

Read the full poll here (.pdf)

In fact, Romney would be the first GOP presumptive presidential nominee since 1996 to head into his nominating convention with a net-negative favorable/unfavorable score.

In 1996, Bob Dole’s score was 39 percent to 36 percent; in 2000, George W. Bush’s was 52 percent to 32 percent; and in 2008, John McCain’s was 42 percent to 30 percent.

Also in the poll, 43 percent say that what they have seen, heard or read about Romney gives them a less favorable impression of the candidate, versus 28 percent who have a more favorable opinion.

For Obama on this same question, 44 percent have a less favorable impression about him, while 27 percent have a more favorable opinion.

This is a noticeable shift for Obama from the summer of 2008, when it was 34 percent less favorable versus 30 percent more favorable.

Asked which candidate is conducting a more negative campaign, 22 percent pick Obama, 12 percent choose Romney, and 34 percent say both are running negative campaigns. 

And asked about Romney’s tax returns – which the Republican candidate says he won’t release prior to 2010 – 32 percent believe that what they’ve heard about the returns give them a more negative opinion of Romney. That’s compared with 4 percent who have a more positive view, and four in 10 who say the returns don’t make a difference.

Economic pessimism vs. economic messaging
Here’s another change from June: growing pessimism about the economy.

According to the new poll, just 27 percent think the U.S. economy will improve in the next year, which is down eight points from last month.

What’s more, a majority of respondents – 55 percent – say they are less optimistic about the economy after what they have seen, read and heard in the last few weeks. That’s up six points from June.

Just 44 percent approve of the president’s handling on the economy, which is a two-point increase from last month. And his overall job-approval rating stands at 49 percent, also up two points from June.

This economic pessimism has given Romney more than an opening in this presidential contest.

The former Massachusetts governor holds a seven-point lead over Obama (43 percent to 36 percent) on which candidate has better ideas to improve the economy, and he holds a nearly identical edge (43 percent to 37 percent) in dealing with the economy.

Read the full poll here (.pdf)

But when it comes to economic messaging, it’s the president who has the advantage.

A whopping 80 percent of respondents say they would be more likely to vote for a candidate who “will fight for balance and fairness and encourage the investments needed to grow our economy and strengthen the middle class” – which happens to be Obama’s message on the campaign trail.

By contrast, 68 percent say they would be more likely to vote for a candidate who “wants to restore the values of economic freedom, opportunity and small government” – which is essentially Romney’s message.

In addition, Obama leads Romney by 16 points (49 percent to 33 percent) on which candidate better looks out for the middle class.

Romney’s likeability and values deficits
While pessimism about the economy is Obama’s vulnerability, Romney’s is a likeability deficit.

A combined 47 percent say they like Romney personally, including 19 who disapprove of his policies. But that’s compared with 67 percent who say the same about Obama.

Another shortcoming for Romney is that voters don’t necessarily relate to him. Just 42 percent say that he has a background and set of values that they can identify with, while 50 percent say that about the president.

The NBC/WSJ poll was conducted of 1,000 registered voters (including 300 by cell phone) from July 18-22, and it has an overall margin of error of plus-minus 3.1 percentage points.