(CNN) - When it comes to insults and accusations in modern politics, few things are worse than being compared to Sen. Joseph McCarthy, whose unsubstantiated accusations in the 1950s against Americans he suspected of communism are widely seen as one of the darkest times in congressional history.
Now, ahead of a House Oversight Committee vote Thursday to hold former IRS official Lois Lerner in contempt, the committee's top Democrat, Elijah Cummings, D-Maryland, is accusing Chairman Darrell Issa, R-California, of engaging in McCarthyism.
And he's releasing a congressional study that he says proves it.
Cummings and fellow committee Democrats say Issa is trampling on Lerner's constitutional rights by holding her in contempt, even though she invoked her Fifth Amendment right not to testify.
Aides to Cummings provided CNN with findings from the nonpartisan Congressional Research Service that cited 11 times in modern history where witnesses were prosecuted for refusing to answer committee questions after invoking their Fifth Amendment rights.
The majority of the instances were in the McCarthy era against witnesses involving alleged communist activities.
"We oppose Chairman Issa's efforts to re-create the Oversight Committee in Joe McCarthy's image, and we reject his attempts to drag us back to that shameful era in which Congress tried to strip away the constitutional rights of American citizens under the bright lights of hearings that had nothing to do with responsible oversight and everything to do with the most dishonorable kind of partisan politics," said Cummings in a report he prepared for the committee's Democratic minority.
Cummings points to the service's research that none of the cases involving witness testimony was ultimately upheld in court.
"Chairman Issa has identified no historical precedent for successfully convicting an American citizen for contempt after that person has asserted his or her Fifth Amendment right not to testify before Congress. The only other times in recent memory that Congress attempted to do this were a disgraceful stain on our nation's history," said Cummings.
Issa and fellow Republicans argue Lerner waived her Fifth Amendment privilege by professing her innocence before citing her constitutional right to refuse to answer questions.
Democrats disagree. As part of their report released to CNN, they list more than 30 legal experts who agree.
The bitter battle over Lerner's testimony and whether to hold her in contempt exploded in partisan and personal terms recently, to the point where Issa was forced to apologize to Cummings for cutting off his microphone during a committee hearing.
But Issa has not backed down and has the blessing of the House GOP leadership to go ahead with the contempt vote. Anger about allegations that the IRS unfairly targeted tea party groups roils the GOP base, and Lerner and her refusal to testify has become a potent political symbol for Republicans.
Issa says she is central in their investigation about IRS abuse and argues they can't go forward without her testimony.
Meanwhile, a second committee, the House Ways and Means, plans to hold a vote Wednesday approving a letter to Attorney General Eric Holder calling on the Justice Department to pursue criminal charges against Lerner.
A GOP source familiar with the committee's plans says the letter will accuse Lerner of improperly influencing the IRS against conservative organizations and misleading investigators.
CNN's Craig Broffman contributed to this report