President Obama was caught on a hot mike in South Korea suggesting to Russian President Dmitry Medvedev that he would have “more flexibility” in missile defense negotiations after he wins reelection.

“On all these issues, but particularly missile defense, this can be solved, but it’s important for him to give me space,” Obama said of incoming Russian President Vladi­mir Putin, who will replace Medvedev in May. “This is my last election. After my election, I have more flexibility.”

This statement is 100 percent true.

“The fact is that we’re in the middle of a presidential campaign,” said former Maine senator and Defense Secretary Bill Cohen in an interview on MSNBC’s “Andrea Mitchell Reports” today. “Any issue of great substance is not going to be decided or debated.”

Unfortunately for Obama, it’s also a pretty big gift for Republicans, who were already set to rehash Obama’s first-term health care agenda this week and plan to argue that the president would do bigger (read: more liberal) things as a lame duck president.

Monday marks the beginning of the Supreme Court hearings on an Obama health care bill that played a major role in handing control of the House to Republicans two years ago. Opposition to that bill was the greatest motivating factor for Republican voters in 2010, and even Democrats acknowledge that it cost them.

Part of the reason the bill was so contentious is that it was viewed as overly ambitious. Obama, despite the warnings of many in his party, pushed forward to make good on his campaign trail promise of taking on big challenges and producing big results — not for political gain but because it’s the right thing to do.

The video of the man sitting across from Medvedev projects a very different image. The hot mike that catches Obama talking about the stark political realities of his job allows Republicans to argue that, not only is Obama a political person focused on his reelection campaign, but that he would be ever more so without the prospect of running again looming.

View Photo Gallery: Many political leaders have been caught making statements not intended for the public.

And for a Republican Party that isn’t as motivated as it was two years ago, that’s a gift. Fear of the future, after all, is a great motivator.

Indeed, Republicans began pouncing on Obama’s flub on Monday afternoon, with the Republican National Committee releasing a web video suggesting Obama has much more in store.

“What else is on Obama’s agenda after the election that he isn’t telling you?” the web video asks.

Mitt Romney, meanwhile, echoed that strategy during an appearance in San Diego. According to the Los Angeles Times, he said: “This is no time for our president to be pulling his punches with the American people and not telling us what he’s intending to do with regards to our missile defense system, with regards to our military might, and with regards to our commitment to Israel and with regard to our absolute conviction that Iran must have a nuclear weapon.”

Democrats do have a defense here. Namely, they can point out, as Cohen did, that it’s just much harder politically to do things in an election year.

“For the president to try and raise a reduction in arms at the strategic level during the course of this campaign would be attacked immediately by Republicans,” Cohen said. “And there’s no chance really of ever moving forward on it.”

Obama campaign spokesman Ben LaBolt says the president has kept nothing hidden about his agenda.

“Whether it’s a month from now or three years from now, there is no secret about the president’s agenda: ensuring that our economy is built to last, where hard work and responsibility are rewarded, the middle class is secure, and everyone plays by the same set of rules,” LaBolt said.

Nothing in the president’s words are surprising; lame duck presidents, unencumbered by reelection concerns, are often more ambitious with their agendas than they were in their first terms.

Given the traction Republicans got after the health care bill, stimulus bill, etc., they were already planning to use the concept of a lame-duck Obama to rouse the base and get people to vote against sending Obama back for a second term. (See: Rick Santorum’s “Obamaville” videos.)

Obama just handed them a cudgel with which to do it.