But the Romney-Ryan plan calls for defense spending at 4% of GDP, which would lead to an increase of $2.1 trillion in defense spending over 10 years, according to an estimate done earlier this year for CNNMoney. But when Biden yielded that figure last week, Ryan said that was not the plan.
"So we're saying don't cut the military by a trillion dollars. Not increase it by a trillion, don't cut it by a trillion dollars," Ryan said during the debate.
But Ryan never explained what the increase would add up to. Romney may have to do that math for America.
Could the longest war go even longer than planned?
The president's plan has U.S. combat troops scheduled to be out of Afghanistan by the end of 2014.
Biden, on Thursday, stated it clearly enough.
"We will leave in 2014," he said. He did not mention the intention to maintain an estimated 10,000 to 15,000 troops in Afghanistan to help with any further training, advising and, if needed, to deal with threats to America's own interests, though not by definition for combat.
Ryan left open the door for troops staying beyond that date, though the Republican ticket agrees with the 2014 transition date.
Raddatz: You're saying that's not an absolute, but you won't talk about what conditions would justify ...
Ryan: Do you know why we say that?
Biden: I'd like to know... (crosstalk)
Ryan: Because we don't want to broadcast to our enemies "put a date on your calendar, wait us out, and then come back." We want to make sure ...
The day after the debate, however, Ryan's spokesman Brendan Buck told CNN that the candidates are committed to the same 2014 transition date as Obama but "believe troop withdrawals within that time frame should be directed by the advice of commanders."
So that leaves some confusion about the Romney-Ryan stance.
Of course, any decision to stay beyond 2014 is not just up to the U.S. It is a matter that would need to be renegotiated with Afghanistan. In addition, the idea that combat could continue might not sit well with a war-weary nation and a military community that already has a 2014 goal post in front of them.