A bill has been introduced in Congress that would prohibit companies from getting federal contracts if they were delinquent in paying taxes.
"Studies by the Government Accountability Office have repeatedly shown that thousands of federal contractors owe over a billion dollars in unpaid taxes," says a press release issued by one of the bill's sponsors, Rep. Brad Ellsworth (D-IN). Under current law, applications for government contracts aren't affected by whether the applicant has failed to pay taxes.
The other sponsor of the bill is Sen. Claire McCaskill (D-MO). President Barack Obama c0-sponsored a similar bill last year in the Senate.
See Ellsworth's press release and the text of H.R. 572, the Contracting and Tax Accountability Act of 2009.