Tax cheaters. Offshore trusts. Tax-avoidance scheme operators. Individual taxpayers.

All have been targets of the IRS in what has become an aggressive war over tax compliance.

In fact, over the last few years, the IRS has established unlikely allies to combat the growing threat of tax cheaters. MasterCard is even in cahoots with the taxman.

If you're a tax cheater and you've survived this long, consider yourself lucky.

A timeline of the war:

November 2003: The U.S. Senate Finance Committee holds hearings examining tax shelter abuses. Among those to testify is a man with his identity and voice disguised to protect him from retribution.

December 2003: The U.S. Justice Department files a lawsuit against Big Four accounting firm KPMG LLC, alleging that the company has obstructed the IRS's investigation of illegal tax-avoidance schemes allegedly promoted by KPMG.

January 2004: IRS Commissioner Mark W. Everson promises more audits.

April 2004: U.S. Justice Department reports a 35 percent increase in the number of tax cheaters referred for criminal prosecution.

May 2004: IRS announces June deadline for taxpayers to come forward if they have employed the “Son of Boss” tax shelter.

June 2004: Through partnerships with 48 states and the city of New York and the District of Columbia, the IRS identifies 28,000 possible tax cheaters.

July 2004: 1,500 taxpayers come forward and admit to using “Son of Boss.”

December 2004: Chemical giant Hercules settles a case with the government in which the IRS alleged that Hercules employed an illegal tax shelter. The company agrees pay $30 million, plus a penalty of about $6 million.

February 2005: IRS identifies dozens of executives, 42 corporations, and more than $700 million in stock options related to a tax-avoidance scheme. Government offers deal: Come forward to avoid criminal prosecution.

April 2005: IRS obtains more than 100 injunctions against promoters of tax-avoidance schemes.

June 2005: U.S. Tax Court threatens to impose fines of up to $25,000 for people bringing frivolous tax-avoidance claims.

July 2005: IRS reports $4 billion in settlements from “Son of Boss.”

December 2005: IRS reports enforcement revenues are up 10 percent to a record $47.3 billion.

January 2006: Richard Hatch, who won $1 million on the original Survivor, is convicted on tax evasion charges.

February 2006: Will you be the IRS's next target?