Tom DeLay, the former Republican congressional leader known as The Hammer for his brass-knuckles style, was convicted of criminally crossing the line into dirty politics.

A Texas jury found DeLay guilty of one charge of laundering corporate money into political donations and one charge of conspiracy. He could face a lengthy prison sentence.

The former House majority leader vowed to appeal the ruling and said he hoped he would be able to get his case heard by “people that understand the law.”

“This is an abuse of power, and it is a miscarriage of justice,” he told reporters.

“I still maintain that I am innocent, that the criminalization of politics undermines our very system, and I’m very disappointed in the outcome.”

Prosecutors argued that Mr DeLay, once among the most powerful Republicans in the US Congress, schemed to influence the Texas elections in 2002.

At the heart of the case was one transaction: Mr DeLay’s political committee in Texas sent 190,000 dollars of corporate donations to the Republican National Committee, which in turn donated the same amount to seven Texas candidates supported by DeLay.

Texas law prohibits corporate giving to candidates. The pivotal 2002 contest became the first step in Mr DeLay’s plan to redraw the state’s congressional districts and tighten his grip on the leadership post by enlarging the Republican majority in Congress.

By 2004 Mr DeLay had accomplished all of that, but a year later a Texas grand jury handed up the felony indictments on charges of money laundering and conspiracy and Mr DeLay was forced to resign as House majority leader.

He retired from Congress, after 22 years, in the middle of his reelection bid in 2006. Craig McDonald, director of Texans for Public Justice whose complaint to prosecutors helped trigger the investigation of Mr DeLay, praised the verdict.

“We can’t undo the 2002 elections, but a jury wisely acted to hold Mr DeLay accountable for conspiring to steal it,” he said.