Although today’s been a big day for U.S. president Barack Obama, it’s been nearly as big a day for his vice president, Joseph Biden, who was also sworn in for a second term as vice president — and a vice president who’s had a very important role to play in the Obama administration with respect to foreign policy.

Biden, who first ran for president in 1988, and who served in the Senate from Delaware from 1973 until becoming vice president in 2009, hasn’t exactly made it a secret that he harbors presidential ambitions in the future.

Even if Biden ultimately decides against a run, his ability to project a credible shot at a 2016 campaign means that he won’t descend into lame-duck status over the next four years, which means he’ll be as relevant as ever on international policymaking.

He’s had a few good news cycles recently, and as outgoing secretary of state Hillary Rodham Clinton starts to bid farewell to the limelight to consider the next stage of her own career, it’s worth noting that if Clinton and Biden both run for the Democratic presidential nomination in 2016, Biden won’t be a pushover — though Clinton is currently very much the favorite.  Biden, who’s 70, isn’t so much older than Clinton, age 65 and recently subject to her own health scare (Ronald Reagan was the oldest person to be inaugurated, at age 69 when he took office in 1981).

Even The Washington Post‘s Ezra Klein thinks Biden is a serious contender.

So in between bouncing around inaugural balls, here are five quick points on why you can’t dismiss Biden — and why he’ll continue to retain political currency on the U.S. foreign policy conversation as 2016 approaches:

• Lingering Obama-Clinton tensions from the 2008 primary campaign, which never fully disappeared, mean that at least part of the Chicago-based Obama campaign and veterans of the Obama-era White House will be willing to give a Biden campaign at least the benefit of the doubt.

• The White House seems inclined to shine credit generously on Biden, including the recent budget deal struck apparently between Biden and Senate Republican minority leader Mitch McConnell and assembling the gun control legislation package, not to mention spearheading oversight to the $700-plus stimulus program (despite grumbles about funds that landed in the hands of now-bankrupt solar power startup Solyndra, no one accused the Obama administration of any real corruption in doling out funds) and even coining the term ‘BFD’ on the day Obama signed national health care reform in 2011 after microphones caught him telling Obama his accomplishment was a ‘big fucking deal.’

• He will be the only Democrat in 2016 with as much foreign policy experience as Clinton.  Although she has served to great reviews as secretary of state for the past four years (short of the Benghazi consulate attack), Biden has been arguably more involved as vice president with respect to foreign policymaking decisions, especially with respect to pulling U.S. troops out of Afghanistan.  He served with distinction through ten years as either chair or ranking member of the Senate Foreign Relations Committee, where he foresaw the de facto splitting of Iraq into Kurdish,  (to say nothing of his ten years on the Senate Judiciary Committee, where he spearheaded Democratic efforts against Supreme Court justice nominees Robert Bork and Clarence Thomas).

• Biden will be able to compete with Clinton on campaign cash, if for no other reason than major Democratic donors will feel obligated to max out their contributions to him as well, in honor of what will likely be eight years of loyal service to the Obama presidency.  Again, going back to the first point, in a Biden-Clinton showdown, who do you think will get the Obama for America excel spreadsheets?

• Although his off-the-cuff comments and sometimes goofy ‘crazy uncle Joe’ persona have often gotten Biden in trouble, he has a genuine likability both among the general electorate and among the kind of blue-collar, working-class (yes, mostly white) Democrats that Clinton appealed to in the 2008 primaries and that Obama had trouble connecting with, both in the 2008 primaries and in the 2008 and 2012 general election.

Nearly everyone’s money is still on Clinton for the 2016 nomination — if she wants it.

But a Biden-Clinton fight wouldn’t necessarily be a cakewalk, and if Clinton takes a pass, for health or any other reason, Biden would have an even stronger advantage against a field whose only real heavyweights appear to be New York governor Andrew Cuomo and Virginia senator Mark Warner, though Massachusetts governor Deval Patrick, newly elected Massachusetts senator Elizabeth Warren and Maryland governor Martin O’Malley may also enter the race.