Texas Judge Pat Priest, who is presiding over the case against the Republican, issued the ruling after a hearing late last month in which DeLay's attorney argued that the indictment was fatally flawed.
When he was indicted in September, DeLay was required under House rules to relinquish the leadership post he had held since 2003. While Monday's ruling was a partial victory for DeLay, he cannot reclaim his post because he remains under indictment.
The ruling means the case will move toward a trial next year, though other defense objections to the indictments remain to be heard by the judge.
"The court's decision to dismiss Ronnie Earle's numerous charges against Mr. DeLay underscores just how baseless and politically motivated the charges were," DeLay spokesman Kevin Madden said, referring to the Democratic district attorney who brought the case.
"Mr. DeLay is very encouraged by the swift progress of the legal proceedings and looks forward to his eventual and absolute exoneration based on the facts and the law."
After the judge's decision, DeLay declined to speak with reporters as he entered a Houston hotel for a campaign fundraiser.
In a written statement, Earle's office said prosecutors were studying the ruling and had made no decision about whether to appeal. Prosecutors have 15 days to challenge the decision.
While Delay's office claimed it was a victory, the decision has created tremendous political problems for the Congressman, said CBS News correspondent Gloria Borger. DeLay is going to trial, and Borger reports many of the rank and file Republicans she talks to are becoming restless, some saying they think he should never return to his post because
DeLay, 58, and two GOP fundraisers, John Colyandro and Jim Ellis, are accused of illegally funneling $190,000 in corporate donations to 2002 Republican candidates for the Texas Legislature. Under Texas law, corporate money cannot be directly used for political campaigns, but it can be used for administrative purposes.
CBS News legal analyst Andrew Cohen reports the decision is good news for DeLay because it narrows the scope of the case against him and other defendants. By kicking out the conspiracy charge but keeping in place the money laundering charge, it makes it tougher, but not impossible, for prosecutors to gain a conviction because it requires them to focus more in specific DeLay acts, Cohen said.
In asking that the case be thrown out, DeLay lawyer Dick DeGuerin argued that one of the charges — conspiracy to violate the Texas election code — did not even take effect until September 2003, a year after the alleged offenses occurred.
Prosecutors, however, said the crime of conspiracy was already on the books, and could be applied to the election code even though such uses were not explicitly in state law at the time.
The judge was unpersuaded by that argument, and dismissed the conspiracy charge. But the judge upheld charges of money laundering and conspiracy to commit money laundering. Those charges involve an alleged attempt by DeLay to conceal the source of the campaign contributions by funneling the money through his own political action committee and then an arm of the Republican National Committee.
In trying to have those charges thrown out, the defense argued that the Texas money laundering law does not apply to funds in the form of a check, just coins or paper money. But the judge said that checks "are clearly funds and can be the subject of money laundering."