From msnbc.com's Tom Curry:  According to NBC's Jim Miklaszewski, the Defense Department puts the cost of the U.S. military operation against Libya’s Gadhafi regime at $550 million through March 28. On a per diem basis, that would average out to about $55 million a day.

Defense Department officials also said that with non-U.S. NATO forces now assuming most of the burden of the Libya mission, the U.S. military cost should be approximately $40 million over the next three weeks. That would equate to less $2 million a day.

Obama has stressed the cost reduction argument in his speeches on Libya, saying Monday night, “Because of this transition to a broader, NATO-based coalition, the risk and cost of this operation -- to our military and to American taxpayers -- will be reduced significantly.”

Obama added that “if we tried to overthrow Qaddafi by force” the dangers to U.S. forces “would be far greater. So would the costs and our share of the responsibility for what comes next. To be blunt, we went down that road in Iraq.”

Welcome to the era of what political scientist Michael Mandelbaum calls “the Frugal Superpower.”

How does the cost so far of the Libya intervention compare to the U.S. military operations in Afghanistan and Iraq?

According to an estimate by the Congressional Budget Office, the Afghanistan operation in the current fiscal year will cost $110 billion, which would average out to more than $300 million per day.

At the height of the Iraq conflict – at least in terms of cost, if not in terms of intensity of combat – it cost $140 billion in fiscal year 2008. That would equate to about $383 million a day.

CBO cautions that most appropriations for Afghanistan and Iraq and for related activities "appear in the same budget accounts as appropriations for DoD’s other functions," so it's not possible "to determine precisely how much has been spent" on those two wars, but CBO's is probably the best estimate we have.

Defense Secretary Robert Gates testified to the House and Senate Armed Services Committees last month that by the end of calendar year 2011, he expects there to be fewer than 100,000 troops deployed in both Iraq and Afghanistan with “virtually all of those forces in Afghanistan.”

This will allow him to “begin reducing Army active duty end strength by 27,000 and the Marine Corps by somewhere between 15,000 and 20,000,” Gates said. That will mean reduced future payroll, health care, and other costs.

But maintaining 100,000 troops in the field remains a very expensive proposition.

The larger picture is that the Defense Department this fiscal year will spend about $712 billion (or 19 percent of total federal spending), according to the CBO. That works out to about $1.95 billion a day.

If there were no Iraq and Afghanistan operations in the current fiscal year, Pentagon spending would be about 20 percent less – assuming the money now being spent in Iraq and Afghanistan weren’t used for some other military purposes.

From NBC's Jim Miklaszewski
The Pentagon reports that through March 28, the U.S. military operation has cost $550 million. The bulk of that is for munitions. The cost for the 199 Tomahawk missiles fired alone is somewhere between $220 to $298 million.

Pentagon officials say once NATO forces takeover the bulk of the mission, the U.S. military cost should be approximately $40 million over the next three weeks.

From NBC's Jim Miklaszewski and Ken Strickland
Gen. David Petraeus has ordered an investigation into the Rolling Stone report alleging that Lt. Gen. William Caldwell improperly used "Psychological Operations" forces to target visiting dignitaries, including Sens. John McCain, Carl Levin, and even Joint Chiefs Chairman, Adm. Mike Mullen.

Meanwhile, Levin -- chairman of the Senate Armed Services Committee -- issued this statement:

For years, I have strongly and repeatedly advocated for building up Afghan military capability because I believe only the Afghans can truly secure their nation's future. I have never needed any convincing on this point. Quite the opposite, my efforts have been aimed at convincing others of the need for larger, more capable Afghan security forces, and that we and NATO should send more trainers to Afghanistan, rather than more combat troops. I am confident that the chain of command will review any allegation that information operations have been improperly used in Afghanistan.

From NBC's Jim Miklaszewski
U.S. sources who have been closely involved in the Egyptian crisis tell us that "Mubarak is going nowhere," at least for now, and that they were "taken by surprise," by tonight's announcement.

They, too, are concerned about Mubarak's statement (according to the translator) that to restore confidence in the economy Mubarak would "federalize the streets." (U.S. presidents have "federalized" military forces to confront segregationists, anti-war protestors, etc.).

According to one official however, "We have assurances, both PRIVATE and public that the [Egyptian] military would not fire on the people."

Intelligence officials are also scrambling to try to determine exactly what this all means. According to one official, "We didn't know exactly what Mubarak was going to do tonight. There was an assumption he would step down, but it looks like he's got other ideas."

From NBC's Jim Miklaszewski and Courtney Kube
A U.S. Army spokesperson confirms that Staff Sgt. Sal Giunta is not going to re-enlist when his tour is up in mid-June.

Giunta, the first living recipient of the Medal of Honor since the Vietnam War, had hinted for several months that he was keeping his options open and considering going to school. But he decided last week to use his GI benefits and get his undergraduate degree.

Giunta and his wife, Jenny, will move to Fort Carson, CO, later this year. No word yet on which school he will attend, but he will be close to Colorado State University.

From NBC's Jim Miklaszewski
While much was made of the Chinese military's test flight of its latest prototype of the J-20 Stealth Fighter jet during Secretary Gates' visit to Beijing last week, the U.S. is prepared to offer President Hu a little fireworks of its own.

Tomorrow, the U.S. military will launch a Delta-4 rocket at Vandenberg Air Force Base in California to put a new, classified spy satellite into orbit for the highly-secretive National Reconnaissance Office. The NRO network of satellites provides the CIA and Defense Department with overhead imagery and audio intercepts from the world's hot spots, and "places of interest," like China for example.

U.S. officials tell NBC News that this launch had been previously scheduled and the timing which coincides with President Hu's visit is "only a coincidence."

While there's no indication otherwise, that's just what the Chinese said about the J-20 test flight during the Gates visit.