On The Hook Meaning

(idiomatic, often followed by for) In debt; obligated to pay or provide; liable; responsible or blamed.

Example: 1991 Oct. 27, Barbara Presley Noble, "Making a Difference: Lloyd's 'Indentured Servant'," New York Times (retrieved 15 June 2011):
  For now, at least, Mr. Wedell, who is a vice president at the Robinson-Humphrey Company, a subsidiary of Shearson Lehman, is still on the hook for unsettled claims.
2008 Sep. 29, "Washington to Wall Street: Drop Dead," Newsweek (retrieved 15 June 2011):
  Yes, incumbents of both parties—especially those incumbents facing tough re-election campaigns—don't want to be on the hook for this vote.
2010 April 15, Joseph R. Szczesny, "GM's Pension: A Ticking Time Bomb for Taxpayers?," Time:
  Could taxpayers really be on the hook for UAW pensions? Yes.