Politicians are begging their supporters to donate campaign cash. That’s because Friday is a key fundraising marker before the 2012 election.

Fundraising numbers can be a sign of a candidate’s support, or lack of it, and many use the reporting deadlines to make urgent appeals.

Indiana U.S. Senate candidate Richard Mourdock, the state’s treasurer, is trying to raise $50,000 this week - a Tea Party Money Bomb, he calls it in an email.

Raja Krishnamoorthi rails against “Tea Partiers” in his plea to supporters to “donate now” to his suburban Chicago congressional campaign.

Congressman Joe Walsh has a “private roundtable discussion” scheduled for Thursday night. A seat will cost you $100.

And in an email signed “Barack,” President Obama’s campaign promises he will personally call some donors.

Whatever cash the campaigns receive by midnight Friday must be publicly reported next month.