The most striking moment of President Obama's press conference Wednesday was when he went after Sens. Lindsey O. Graham (R-S.C.) and John McCain (R-Ariz.) in no uncertain terms.

Graham and McCain have made clear in recent days that they wouldn't vote to confirm U.N. Ambassador Susan Rice as Secretary of State due to a lingering controversy about what Rice said in the days after the attack on Benghazi, Libya. Rice suggested at the time that the deaths were due to a spontaneous demonstration sparked by an anti-Islam video, but it soon came out that it was a planned attack.

Graham has suggested Rice is "incompetent" and said he doesn't trust her, while McCain said she is "not qualified" to serve as secretary of state.

Obama took umbrage at both men Wednesday.

"If Senator McCain and Senator Graham and others want to go after somebody, they should go after me," Obama said, adding: "When they go after the U.N. ambassador, apparently because they think she’s an easy target, then they’ve got a problem with me."

The moment was a stark reminder of the contentious political environment in which we remain even after last week's election -- something nobody should forget when it comes to the so-called "fiscal cliff" and immigration reform.

In recent days, many big-name conservatives and Republicans have suggested they are willing to give a little more when it comes to revenue increases, taxes and illegal immigration.

And Obama started the press conference by striking a note of bipartisanship as well, even praising McCain for his past support of comprehensive immigration reform and paths to citizenship.

Just minutes later, though, McCain was in the crosshairs, with Obama visibly angry over the attacks on a woman who is seen as the frontrunner to become his next secretary of state. Obama argued that she was merely reciting the (faulty) intelligence that was available at the time and bears little or no responsibility for anything related to Benghazi.

"To besmirch her reputation is outrageous," Obama said.

Graham's office quickly responded to Obama's remarks, hitting back just as hard.

"Mr. President, don’t think for one minute I don’t hold you ultimately responsible for Benghazi," Graham said. "I think you failed as Commander in Chief before, during, and after the attack.   
"Given what I know now, I have no intention of promoting anyone who is up to their eyeballs in the Benghazi debacle.”

McCain was a little more measured in his response, but no less firm: "We owe the American people and the families of the murdered Americans a full and complete explanation, which for two months the president has failed to deliver."

The ramping up of rhetoric over Benghazi should remind us all that both sides have closely guarded prerogatives and political bases that will bristle at the idea of middle ground when it comes to important issues -- whether it's Benghazi or taxes or immigration (the latter on which Graham and McCain just happened to be some of Obama's most likely GOP partners).

Talking about compromise is much easier than effecting it, and the duality of Obama's press conference -- one minute talking about bipartisanship and the next minute engaging in a heated partisan spat -- serves as a reality check.

No matter which side you think is in the right here, the fact is that both sides are dug in and have a huge amount of political capital at stake. What was already a contentious issue in Libya will only become more so after Wednesday's press conference.

And as the two sides settle in for a high-profile negotiations about the future of the American economy, the well of bipartisanship has certainly been poisoned -- at least a little, and maybe a lot.