NEW YORK -- Vice President Joe Biden charged Thursday that a flip-flopping Mitt Romney remains "mired in a Cold War mindset" and has "a profound misunderstanding of the responsibilities of a president and a commander in chief."
In one of the Obama campaign's harshest critiques of former Massachusetts Gov. Mitt Romney to date, Biden accused the GOP's presumptive nominee of cravenly criticizing the president on policies he's previously backed, unwisely planning to "outsource" foreign policy decision-making to the State Department, and being "completely out of touch" with the realities of the global stage today.
And he implied that his boss's chief rival would not have taken the same action as the president in greenlighting a risky operation to kill 9/11 mastermind Osama bin Laden.
"You can't say for certain what Gov. Romney would have done," Biden said of Obama's decision in remarks to a crowd of about 500 students and foreign policy buffs at New York University's School of Law.
Invoking his unofficial slogan for the 2012 re-election campaign -- "Bin Laden is dead and General Motors is alive" -- Biden warned, "You have to ask yourself, if Gov. Romney were president, could he have used the same slogan in reverse?"
Much of Biden's over-45 minute address centered on President Barack Obama's leadership in officially ending the Iraq War, drawing down troop levels in Afghanistan, and pulling the trigger on a bin Laden mission that the vice president said would have ended Obama's political career if it failed.
In each case, Biden argued that Romney at some past point in his political career had voiced support for those objectives but had criticized them for political expediency during the GOP primary.
"In the face of the challenges that we now understand are ahead of us, what would Gov. Romney do?" he asked. "The truth is we don't know for certain but we know where the governor starts. He starts with a profound misunderstanding of the responsibilities of a president and a commander in chief."
Biden, a longtime Democratic leader of the Senate Foreign Relations committee, said that Romney hopes to "outsource" international policy issues to the State Department, citing a 2007 quote in which the former Massachusetts governor said "a president is not a foreign policy expert."
"That kind of thinking may work for a CEO but I assure you it will not and cannot work for a president," Biden said.
In a conference call with reporters held before the vice president's speech, Romney's foreign policy advisers pushed back on the idea that the GOP leader would return the United States to unpopular Bush-era policies, dubbing the current commander-in-chief's worldview a "Carter/Obama doctrine" that deviates from America's traditional exercise of "peace through strength."
The vice president's address was the fifth "framing speech" in a series intended to draw stark contrasts between Obama and Romney, although today's was the first since Romney's GOP rivals Newt Gingrich and Rick Santorum announced their withdrawals from the primary contest.
Biden's tone was somber for much of the speech, although he won laughter from the mostly student-aged crowd when describing the president's decisiveness.
"This guy's got a backbone like a ramrod. For real. For real," he insisted as the audience giggled.
And, quoting the old foreign policy adage to "speak softly and carry a big stick," Biden responded with his own, well, schtick.
"I promise you, the president has a big stick," he said.
NBC's Garrett Haake contributed