And for Biden, still mulling a presidential bid, that could pose a problem.
As he calculates all the angles that would influence his candidacy a decision is reportedly coming within days Biden has more than the looming obstacle of front-runner Hillary Clinton to consider. As a candidate, he would become the chief defender of a foreign policy that critics say has been incoherent and that gets increasingly low marks in public opinion polls.
Beyond Afghanistan, the White House is under fire for its response to Russian action in Syria, where Vladimir Putin has assumed the superpower role there that the United States has declined to take, for the enduring threat posed by Islamic State, and for the Iran nuclear deal that has spiked tensions with ally Israel.
Biden, who prides himself on being a full partner on Obama's national security team, would own all of it. "Foreign policy is a liability for Biden," Democratic strategist Douglas Schoen said.
The Afghanistan shift was a personal setback for Biden, the most influential voice in the administration pushing for hard timelines for the removal of US troops from the country. Clinton, by contrast, favored a more robust military presence there during her tenure as secretary of state during Obama's first term.
Clinton, whose status as the prohibitive front-runner wouldn't change even if Biden jumps in, has distanced herself from Obama by calling for more aggressive action in Syria and opposing the Pacific Rim trade deal. As a sitting vice president, Biden wouldn't have the luxury of distancing himself from Obama's policies, even if he were so inclined.
"How does a presidential aspirant like Joe Biden reach for a bold American foreign policy without fundamentally distancing himself from his boss? It's tough," said Aaron David Miller, a former official in the Clinton and Bush administrations who is now with the Woodrow Wilson International Center for Scholars.
Obama's approval ratings with the US public on foreign policy have tumbled since Biden stood at the Democratic National Convention three years ago and pronounced, "Osama bin Laden is dead and General Motors is alive."
According to Gallup, Obama enjoyed about a 50 percent approval rating on foreign affairs during his first term. That number fell to 36 percent this summer.
National security is often overshadowed in US presidential races by domestic issues, most notably jobs and economic growth.
But with the economy on a firmer footing that means it is not drowning out other issues for voters, some Republicans such as US Senator Marco Rubio of Florida are trying to put more of a spotlight on foreign policy.
Rubio regularly blasts Obama on the campaign trail and said of Biden: "He's been wrong time and again on issue after issue."
"He would be a disastrous commander-in-chief," Rubio told radio host Hugh Hewitt in August, as speculation about Biden's intentions began to swirl.
Biden's reputation took a hit when it was revealed that he had advised against the US military raid that killed bin Laden in 2011.
He was a firm supporter of a reduced US role in Iraq, which the administration's detractors argue created a vacuum that strengthened the rise of Islamic State. Biden also resisted arming rebel groups in Syria.
Clinton recently called for a "no fly" zone in Syria, which both Obama and Biden oppose.
Should he run, Biden "has to establish his own identity," but to do so he would have to highlight times when he privately disagreed with Obama, said Anthony Cordesman, an expert on U.S. security policy at the Center for Strategic and International Studies.
Biden's supporters say he could point to his decades in the Senate, especially his years chairing the Foreign Relations Committee, to counter Republican arguments that he would simply be an extension of Obama's world view. For example, Biden has been friends for decades with Benjamin Netanyahu. Obama, by contrast, has a frosty relationship with the Israeli prime minister.