Sen. Claire McCaskill (D-Mo.) in Washington on Feb. 1. (Manuel Balce Ceneta/AP)

The first lesson in politics is that when you have bad news, the best way to deal with it is to get it all out at once — in hopes of putting it in your rearview mirror as quickly as possible.

And yet, so few politicians seem to learn that lesson. Witness Claire McCaskill’s plane problem.

Earlier this month, Politico reported that the Democratic senator from Missouri had spent $76,000 in taxpayer funds to fly on a private plane co-owned by McCaskill and her husband.

McCaskill quickly reimbursed the Treasury Department, insisting that it was a small oversight, quickly corrected.

Or not.

Reports soon surfaced that McCaskill had occasionally used the plane for purely political trips, refueling the controversy. And then the real turbulence hit.

On Monday, McCaskill acknowledged that she had failed to pay more than $287,000 in personal property taxes on the plane. “I’m being held accountable, like I should be,” she said on a press call about the tax issue. “I made this mistake.”

The optics for McCaskill couldn’t be worse. Not only does she have a private plane — a luxury most people only dream about — but more than a quarter of a million dollars in taxes on said aircraft went unpaid. It amounts to a political double whammy.

Further complicating things is that McCaskill has built her political brand on rooting out fraud and pushing for more transparency in government.

And just when it looked like things had bottomed out for her, the Cook Political Report, a respected political handicapping service, moved the 2012 Senate race in Missouri from “lean Democratic” to “toss up” late Thursday.

Claire McCaskill, for failing to stop your political bleeding, you had the worst week in Washington. Congrats, or something.

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Chris Cillizza writes “The Fix,” a politics blog for the Washington Post. He also covers the White House.