A former finance chairman of the Democratic National Committee (search) pleaded guilty Thursday to threatening to bar an investment company from doing business with the Illinois State Teachers Pension Fund unless it agreed to hire a consultant.

Joseph A. Cari (search) and another man agreed to help federal prosecutors in their investigation of corruption at the pension fund in exchange for a break when they are sentenced.

Cari, 52, a Chicago lawyer, pleaded guilty to one count of attempted extortion. The DNC's national finance chairman in 2000 would face 37 to 46 months in prison under federal sentencing guidelines unless he cooperates.

The second man, attorney Steven Loren (search), pleaded guilty to obstructing the Internal Revenue Service in connection with alleged corruption at the pension fund, which pays the pensions of public school teachers outside Chicago.

In his plea agreement, Cari acknowledged that he had phoned the unnamed investment firm and threatened to have its investment offer removed from the agenda of a pension fund board meeting unless executives of the firm signed a blank contract with a consultant based in the Caribbean.

Cari attorney Scott Lassar (search) declined to comment after the hearing.

Loren could be sentenced to 12 to 18 months if he doesn't meet the terms of the plea agreement.

Also charged in the case is Chicago attorney and entrepreneur Stuart Levine (search), who was a member of the board of the pension fund. He has pleaded not guilty.

Sentencing dates will be set later.