During a family bus trip, former Alaska Gov. Sarah Palin made a claim about the size of the debt accumulated under President Barack Obama.



"Look at the debt that has been accumulated in the last two years," Palin, a Republican, told Fox News’ Greta Van Susteren on May 31, 2011, as her bus rolled down the highway. "It's more debt under this president than all those other presidents combined."



This claim is similar to ones we’ve checked in the past -- with varying ratings -- so we thought we would check Palin’s as well.



A few preliminaries. First, there are two common measures for debt. One, called public debt, tallies up the debt held by the public, while gross federal debt is a larger figure that combines publicly held debt plus debt held by the government itself, such as in the Social Security or Medicare trust funds. Both figures are considered legitimate, and since Palin didn’t specify which one she was referring to, we’ll run the numbers for both categories of debt.



Second, we’ll assume that all the debt accumulated under Obama should be attributed to him. In reality, this isn’t a logical allocation, since the first budget he wrote was actually for the 2010 fiscal year, and because he -- like all presidents -- inherited the fiscal legacy of his predecessor.



Still, calculating it this way is much simpler -- and as we’ll see, it won’t matter to the outcome.



We turned to the Treasury Department’s "Debt to the Penny" calculator, where we found that on Obama’s first day in office, Jan. 20, 2009, the public debt stood at $6.307 trillion; gross federal debt stood at $10.627 trillion. For the most recent date available -- May 27, 2011 -- these two debt figures stood at $9.718 trillion and $14.345 trillion, respectively.



That means that under Obama, the public debt rose by $3.411 trillion and the gross federal debt rose by $3.718 trillion. That’s a huge amount of money -- but it’s far less than what was accumulated by Obama’s 43 predecessors.



Because debt is cumulative (minus any intervening surpluses) the debt level for the previous 43 presidents is equal to the amount of debt on the day Obama was inaugurated. So even by the standards we used -- which aren’t especially favorable to Obama -- the debt he accumulated amounts to either 54 percent of his predecessors’ combined debt (using the public debt figure) or 35 percent (using gross federal debt).



Neither of these figures is "more … than all those other presidents combined," as Palin had said.



Palin would have been correct if she had said the same thing that Rep. Eric Cantor, R-Va., said last fall, that "the budget submitted by Obama will add more to the debt than the outstanding debt of the previous 43 presidents combined." We rated that True.



In other words, Cantor didn’t use the two-year timeline that Palin did -- and making that change improves the accuracy of the claim.



But Palin didn’t say that. She said, quite specifically, that Obama had accumulated more debt in two years than the previous 43 presidents had collectively. And while Obama (along with Congress) has indeed accumulated a lot of debt for various reasons, his two-year debt total, even if you use the most generous standards for judging Palin’s comment, is still $3 trillion to $7 trillion short of the amount needed to make Palin’s statement accurate. So we rate her claim False.