As the inevitable brinksmanship plays out, it's useful to step back and look at just how central a role Biden has played throughout Obama's presidency.

Over the past four years Biden has insinuated himself into the White House, while seeming hardly to try, in a way that no other vice president in memory has done. He and Obama, both consummate pragmatists though they tend to be liberal in outlook, have achieved something close to a mind meld across a whole range of issues, including foreign policy, the economy, and political strategy. Biden said it outright in his speech during the presidential campaign: "I literally get to be the last guy in the room with the president. That's our arrangement." That's no small thing in a town where power is often measured in minutes of presidential face time.

It wasn't long ago that Biden's predecessor, Dick Cheney, was seen as the gold -- some might say sulfurous -- standard in vice presidential power. Biden himself, ironically enough, once described Cheney as "probably the most dangerous vice president we've had" because of what many observers saw as Cheney's undue influence over George W. Bush.

But in terms of the sheer number of issues Biden has influenced in a short time, the current vice president is bidding to surpass even Cheney. Fiscal issues and guns are only a small sampling of this vice president's portfolio. Back in 2010 it was Biden's office that, in the main, orchestrated the handover to the Iraqis. It is Biden's view of Afghanistan that has, bit by bit, come to dominate thinking inside the 2014 withdrawal plan. On financial reform it was Biden who prodded an indecisive Obama to embrace, at long last, Paul Volcker's idea of barring banks from risky trading, according to Austan Goolsbee, formerly the head of Obama's Council of Economic Advisers. The VP also tilted the discussion in favor of a bailout of the Big Three auto companies, according to Jared Bernstein, Biden's former economic adviser. "I think he made a difference in president's thinking," Bernstein said. "He understood the importance of the auto companies to their communities, and throughout the country."

In an interview in the fall of 2010, Biden could hardly contain his enthusiasm for his partnership with Obama. The phrase "Barack and I ... " fell from his lips naturally, with no hint of diffidence. He told me then that to his continuing surprise Obama has continued to "turn over big chunks" of policy to him to handle, whether it's Iraq, middle-class issues, overseeing the recovery act. At an early meeting, "all of sudden Obama stopped. He said, 'Joe will do Iraq. Joe knows more about Iraq than anyone..... The [Economic] Recovery Act, he just handed it over" to Biden, according to a senior administration official who attended the meetings and would talk about internal discussions only on condition of anonymity.