SUMMARY: With just three days until the Iowa caucuses, the candidates are unleashing a flurry of charges — and making a few slip-ups. We find that Biden is overstating his role on Bosnia, that Romney never got an NRA endorsement, that Romney is mostly right that McCain opposes repealing the estate tax and that Obama is wrong about gas prices.

The Christmas peace has ended in Iowa and the presidential candidates are in a furious sprint to Thursday's caucuses. Today we're publishing new Truth-O-Meter rulings on several recent claims by the candidates.

Maybe the icy weather is getting to them — or maybe it's time to throw the proverbial Hail Mary pass. But we're finding the candidates are making more slip-ups and exaggerations:

* Barack Obama slipped on oil recently. He claimed that gas prices and Exxon Mobil's profits "have never been higher." He was wrong on both counts and earned a False.

* Joe Biden, the Delaware senator who once took credit for cutting New York's crime rate, has a TV ad in which he claims he ended genocide in Bosnia. We find he was definitely a vocal member of Congress on the issue but that's quite a stretch too and give him a Barely True.

* Mitt Romney misfired when he said he had received the endorsement of the National Rifle Association. We gave him a False.

* But we also gave Romney a Mostly True for a claim in a TV ad that John McCain "opposes repeal of the death tax." Although PolitiFact bristles at using the loaded term "death tax" to describe the estate tax, we find that Romney is fairly summarizing McCain's position.