In a rare moment of unity between President Barack Obama and congressional Republicans, both parties appear foursquare behind a proposal to provide the White House with trade promotional authority in order to fast-track an Asian free trade agreement. In an even rarer development, the Democratic Party’s left-wing is solidly opposed to providing Obama with new powers.

In an attempt to stop the bleeding on his left flank, Barack Obama sat down with one of their own on Tuesday, MSNBC host Chris Matthews, and explained the logic behind the Trans-Pacific Partnership agreement.

“I would not be doing this trade deal if I did not think it was good for the middle class,” Obama told the MSNBC host. “And when you hear folks make a lot of suggestions about how bad this trade deal is, when you dig into the facts, they are wrong.”

The president specifically singled out progressive icon Sen. Elizabeth Warren (D-MA) who has vocally opposed the proposed trade agreement. “I love Elizabeth,” the president insisted. “We’re allies on a whole host of issues. But she’s wrong on this.”

“The politics around trade has always been tough, particularly in the Democratic Party, because people have memories of outsourcing and job loss,” Obama conceded last week. But prominent Democrats are not backing off their opposition to the TTP merely because Obama is for it, and they appear set to try to demonstrate just what a lame duck the president has become.

“I have never, ever … supported a trade agreement, and I’m not going to start now,” Senate Minority Leader Harry Reid insisted when asked if he would support giving the president new trade authority. “So the answer is not only no, but hell no.”

Former Maryland Gov. Martin O’Malley is also poised to exploit liberal anti-trade sentiment as a means of introducing himself to the Democratic presidential primary electorate as an alternative to Hilary Clinton. In a video released on Tuesday, O’Malley presented himself as the anti-TTP champion in the race.

“We need to focus on making our own economy sustainable, more circular, and making ourselves more strong here at home,” O’Malley insisted. “That’s the best way to engage in trade all around the world.”

Your best guess is on how the domestic economy becomes “more circular” – whatever that means — is as good as anyone’s.

The odd thing about this internecine squabble is that rank and file Republicans more than Democrats are suspicious of free trade. In a post examining New Jersey Gov. Chris Christie’s odd comments calling into question the value of the NAFTA free trade agreement, Allahpundit noted that antipathy toward free trade is far more pronounced among Republicans than it is among Democrats.

You would never know that from watching Democrats fight amongst themselves over the TTP this week.