Michael O'Brien, NBC News

Republican presidential nominee Mitt Romney embraced Bill Clinton's speech this week at the Democratic National Convention, saying the former president's speech — which was full of criticism of Romney — helped "elevate" Democrats' convention.

In his interview airing Sunday on NBC's "Meet the Press," Romney praised the Wednesday night speech by the Democratic ex-president, which ridiculed Romney and Republican vice presidential candidate Paul Ryan on issues ranging from fiscal policy to Medicare.

"He did stand out in contrast with the other speakers; I think he really did elevate the Democrat convention in a lot of ways," Romney said. "And, frankly, the contrast may not have been as attractive as Barack Obama might have preferred if he were choosing who'd go before him and who'd go after."

Clinton's speech was regarded as one of the highlights of the Democratic convention; he formally nominated President Obama for a second term, and his folksy speech built up the current president while simultaneously taking Romney to task. But as Romney suggested, Clinton's speech drew as much interest as Obama's among political observers, and Romney seemed to suggest the former president even overshadowed the current one.

But Clinton's criticism hasn't previously deterred Romney from embracing the former Democratic president. He's praised Clinton on the campaign trail as a centrist, as if to portray Obama as governing well to the left of Clinton.

Romney's tack is an implicit acknowledgement of Clinton's broad popularity, a sentiment the GOP presidential nominee joked would probably propel Clinton to a third term in the White House, if it were legal.

Asked whether Clinton could be elected president today, Romney responded: "If the constitution weren't in his way, yeah. Perhaps. But I don't know the answer to that."