But Biden has hardly taken a back seat. Instead, he has become President Obama’s workhorse on issues from war to budgets to economic recovery. The New Deal Democrat from coal-country Scranton has even become a liberal standard-bearer on same-sex marriage, nudging the president to publicly shift positions. While Gore was given unusually significant responsibilities on very specific areas such as the environment and government efficiency, Biden, much like Cheney before him, has had plenty of running room on an array of key administration policies — a sort of de facto assistant president. …

Biden never really had a chance in his second bid for the Democratic presidential nomination in 2008, running into the Obama-Hillary Rodham Clinton buzz saw. His occasional gaffes continued to be a drag, seized on by opponents who saw him as easy pickings despite his solid work in the Senate. And in the public eye, his perceived lack of discipline masked his knowledge and experience in domestic and foreign affairs.

His vice presidency may have helped him overcome all that. As Biden approaches his 70th birthday in November, one hears talk — certainly not discouraged by him — of a third presidential try in 2016. At 73, he would be one of the oldest Americans to seek his country’s highest office, surpassing Reagan’s 69 in 1980 and equaling Reagan’s age at reelection.