In a quickly arranged conference call with reporters Monday, Sen. Claire McCaskill (D-MO) admitted that she had failed to pay $287,283 in personal property taxes on a private plane.

McCaskill said that she would immediately send a check to St. Louis County to cover the back taxes not paid between 2007 and 2010.

"I have discovered that the personal property taxes on the plane have not been paid," she told reporters. "There should have been a reporting to the county of the existence of this plane. There are people I could blame for this, but I know better. I take full responsibility."

"This was a mistake, It should have been reported in Missouri. It will be paid in Missouri today," McCaskill added.

She said she had campaign lawyers looking into the 89 flights she took on the plane to see if any in-kind contributions needed to be reported. She now plans to sell "the damn plane."

The senator wasn't sure if this would hurt her bid for re-election.

"I've tried to handle everything as forthright and honest as I could," she said, while lauding her own efforts to fight for accountability and transparency. "I am being held accountable because of transparency."

The National Republican Senatorial Committee (NRSC) released a web video Monday, taking advantage of the controversy.

The video reminds viewers that McCaskill once said, "If my walk doesn't match my talk, shame on me and don't ever vote for me again."

Republicans will have plenty more ammunition if they decide to continue this line of attack. McCaskill has introduced legislation which would demand federal employees pay their taxes or risk being fired.

This video is from the NRSC, uploaded March 21, 2011.