Politicians love microphones, but they don’t always treat them with the respect they deserve. Hence trouble this week for Barack Obama, who was recorded in conversation with Russian president Dmitry Medvedev at the nuclear security summit in South Korea — a conversation he almost certainly would not have embarked on had he realised the microphone was live.

Referring specifically to missile defence, Obama said “this can be solved but it’s important for him [ie Vladimir Putin] to give me space … After my election I have more flexibility.” Medvedev expressed his understanding and promised to relay the message to Putin, who succeeds him in the presidency in May.

There’s nothing very surprising in the remarks themselves, and it’s no more than common sense for Obama to think he’ll be better placed to come to an agreement with Putin once this year’s election is over. But common sense doesn’t always make for good politics, and Republicans seized on the conversation as evidence Obama would betray American interests as soon as he no longer had to fear electoral retribution.

The White House, of course, was having none of this, and Obama patiently explained to reporters that negotiations on defence subjects would benefit from some bipartisan support — something that’s currently in short supply: “Frankly, the current environment is not conducive to those kinds of thoughtful consultations. I think the stories you guys have been writing over the last 24 hours [are] pretty good evidence of that.”

It’s not the first time the president has fallen for the open mic trap. A few months ago, in what they thought was a private conversation, Nicolas Sarkozy told him he couldn’t stand Israeli prime minister Benjamin Netanyahu, to which Obama replied along the lines of: “You’re sick of him? I have to work with him every day.”

Still, it’s interesting that Obama’s unguarded thoughts tend to show a preference for peace, whereas Republican gaffes lean the other way: as with Ronald Reagan’s “we begin bombing in five minutes”, or John McCain on the campaign trail singing “Bomb bomb Iran”.

Which brings us to Mitt Romney, the presumptive Republican nominee to face Obama in November, who keeps showing a remarkable ability to turn positives into negatives by overreaching. Romney told CNN’s Wolf Blitzer that “for this President to be looking for greater flexibility, where he doesn’t have to answer to the American people in his relations with Russia, is very, very troubling”, and then, not content with that political point, went on to describe Russia as “without question, our number one geopolitical foe”.

That’s not a crazy position to hold, but it’s an inflammatory one for a presidential candidate to express, and it quickly took the focus off Obama. Medvedev responded that Romney was using “ideological cliches” and that candidates should “use their head and consult their reason”.

But it’s a good illustration of the backward-looking nature of today’s Republican politics. The last 30 years of change in Russia have passed them by; whereas Reagan eagerly embraced Gorbachev’s reformism, Romney and the rest are stuck in the mindset of the Cold War. As the controversy over the Georgian war in 2008 showed, they reflexively see Russia in Soviet-era terms as the aggressor, regardless of the reality.

It’s almost as if, not caring about democracy themselves, they see the fact Russia has (imperfectly) democratised as completely beside the point. It’s all about imperial rivalry, and imperial interests are timeless.