Rep. Dennis Kucinich hasn’t said whether he will run for president in 2012, but the liberal Ohio Democrat seems to be acting like a candidate with his recent crusade against President Barack Obama on Libya.

Today, Kucinich will take to the House floor to offer his rebuttal to Obama’s Monday night speech outlining reasons for international attacks on Libyan dictator Moammar Gadhafi’s military. Kucinich has long been an anti-war advocate, but this time, he’s challenging the policies of a president from his own party.

“I am making a principled challenge to the actions of the administration, and I can’t tell you that I’m doing it with any enthusiasm because it’s not easy to challenge individuals who you otherwise have an affection for,” Kucinich said in an interview this week. “This goes beyond friendship, it goes beyond party; it goes to principles involved in finding this nation.”

Kucinich, who twice ran for the presidency on an anti-war platform, said he “hasn’t really been thinking about” waging a primary challenge to Obama in 2012. But he nevertheless said the president violated the Constitution by committing U.S. troops to enforce a no-fly zone over Libya without first getting Congress’ approval. And he has vowed to push an amendment into the next continuing resolution to block funding for the effort.

Democratic aides note that Kucinich’s anti-war rhetoric is nothing new, and they say most Members are relatively unfazed by his latest offensive on Libya. But Kucinich has been attracting the attention of media outlets and has found some uncommon Republican bedfellows in the process.

“I don’t know if he’s a renewed leader as much as the subject he’s most vocal about is again in the news,” one House Democratic aide said.

Even Kucinich admits that a moment has met opportunity when it comes to challenging Obama’s position on Libya.

“When a platform presents itself … I’ve not hesitated to speak out on these issues,” Kucinich said. “I was active in challenging what I felt was an abuse of war powers by the Clinton administration, the Bush administration. It’s not as though I’ve taken a partisan approach to this.”

Kucinich sought the presidency in 2004 and again in 2008, largely because of his opposition to the wars in Iraq and Afghanistan.  Kucinich attempted to bring articles of impeachment against then-Vice President Dick Cheney in 2007 and later against President George W. Bush in 2008, primarily over the war in Iraq. And for years, Kucinich has advocated for the establishment of a Department of Peace.

On Libya, Kucinich has teamed up with Rep. Ron Paul (R-Texas), who ran for the White House in 2008, and Rep. Walter Jones Jr. (R-N.C.) on the amendment to CR. The alliance is a familiar one for Kucinich, who worked with Jones earlier this month on a resolution calling for a withdrawal of troops in Afghanistan. That resolution won 93 votes.

So far Democratic leaders have not tried to quiet Kucinich’s stance on Libya, even as it opens Obama up to criticism from within his own ranks. In fact, House Democratic Caucus Chairman John Larson (Conn.), who like Kucinich said that Congress should have been called back from recess last week to consider a declaration of war, credited his colleague for his outspoken position on the issue.

“I think Dennis is not only a voice in the Caucus, he’s a national voice,” Larson said. “It’s not that all of the members of our Caucus will agree with his position, and he may take a harder, more edgy point of view. But even if they don’t support him, they’ll nod their heads and say he had the nerve to say something that was difficult.”

Asked this week whether he thought Kucinich might run for president in 2012, Ohio Republican Rep. Steven LaTourette said: “Never say never.”

Kucinich said he plans to challenge Democratic leaders for deciding to back Obama on Libya before rank-and-file Members had been consulted. And while Kucinich demurred on whether he will make a third White House bid next year, he said he did plan seek a ninth term to the House in 2012. Ohio will lose two seats in redistricting next year and Kucinich’s Cleveland-based district stands to be vastly changed or even done away with. Accustomed to fighting uphill battles, the former Cleveland mayor said he would press on.

Kucinich ended up dropping out of the presidential primary contest in January 2008 in part because he was facing a primary challenge for his House seat.

“It’s already been widely established that my district will either be altered or abolished, but that’s a year and a half from now,” Kucinich said of redistricting. “Sometimes you have to take a stand without regard to what the political consequences are going to be. I’m not seeking to curry favor with what I’m doing. If you don’t take a stand, what are you here for? This isn’t ‘Dancing with the Stars.’”