A former state legislator who changed parties in 2003, then cast a key vote to keep Democratic House Speaker Jim Black in power, pleaded guilty Tuesday to conspiring to accept $50,000 in campaign contributions to make the switch.

Former Rep. Michael Decker pleaded guilty in federal court to one count of conspiring to extort money. In exchange, Decker supported a particular candidate for speaker, prosecutors said.

The prosecutors didn't mention Black's name during the hearing or in a document that detailed the charges. Those from whom the money was said to be extorted also were not identified.

Decker switched to the Democratic Party just before the 2003 legislative session after 18 years as a Republican legislator. His turned a one-vote Republican majority into a 60-60 tie, allowing Black to share power with his GOP counterpart in the narrowly divided House chamber. Black later regained the speaker job outright.

Decker switched back to the Republican Party after the session but was defeated in the 2004 GOP primary.

Sentencing was set for Nov. 1. The felony is punishable by up to five years in prison and a $250,000 fine.

"This kind of public corruption undermined our democracy and the legitimacy of legislative bodies," acting U.S. Attorney George Holding said in a statement.

Decker declined to comment as he left the federal courthouse Tuesday. A spokeswoman for Black, who has not been charged with any crimes, did not immediately return phone calls seeking comment.

Prosecutors said Decker solicited money and other things of value to switch parties after the 2002 elections. Decker received $38,000 in checks and $12,000 in cash, some of which he converted to his personal use, they said.