WASHINGTON — At a time when the Republican House of Representatives is poised to hold Attorney General Eric Holder in contempt, Democrats in the Senate want to give him broad new powers in elections.

A group of Senate Democrats pushed Tuesday for a new law to combat the use of campaign tactics meant to deceive people into not voting, tactics often aimed at minorities and other vulnerable groups. As part of the law, the group wants Holder, and any future attorney general, to have the power to prosecute offenders. At the same time, it would require the attorney general to step in as an arbiter of the truth in elections, telling the public about deceptive practices and labeling them as false.

The idea of giving Holder powers in elections makes the proposal dead on arrival in the Republican-controlled House, where Republicans are likely to vote Thursday to hold him in contempt for refusing to turn over emails in an investigation of a gun sting operation gone bad. Regardless of who holds the office, Republicans said, the proposed law is unnecessary and unconstitutional.

At a Senate Judiciary Committee hearing Tuesday, Democrats said the bill is needed to address a litany of instances of voter deception and intimidation occurring over the past few years.

In Maryland, for example, Sen. Ben Cardin, D-Md., testified about the 2010 election, when automated phone calls told voters on Election Day that Gov. Martin O’Malley, a Democrat, had already won, so they didn’t need to vote.

“Our goals have been met,” the robo-call told more than 110,000 Democratic voters. “Relax. Everything is fine. The only thing left is to watch on TV tonight.”

In Houston in 2010, fliers were distributed in African American neighborhoods telling voters that they need only cast their ballot for one Democratic candidate to vote for the party’s entire ticket.

Earlier this month, calls tried to dissuade people from voting against Wisconsin’s Republican governor in a recall election. The calls falsely told voters that if they’d signed a recall petition against Gov. Scott Walker, their “job was done” and they didn’t need to actually vote to oust him.

Sen. Charles Schumer, D-N.Y., said such tactics were “despicable.”

“People like this really belong in jail, because they’re really violating the practice of our democracy,” Schumer said.

Such practices often target people of color, people with disabilities and the young, poor and elderly, testified Tanya Clay House, director of public policy at the Lawyers’ Committee for Civil Rights Under Law. Similar tactics date to Jim Crow laws and unlawful tactics targeting African American voters, said Sen. Patrick Leahy, D-Vt., in written testimony.

“Pictures of Americans beaten by mobs, attacked by dogs, and blasted by water hoses for trying to register to vote are seared into our national consciousness,” said Leahy. He argued that the problem is worsening through new laws requiring voters to show identification.

Targeted communities tend to be primarily Democratic, House said.

“I am not going to assume what their (Republicans’) intent is,” House said. “But because these fliers are targeting certain vulnerable communities, I think certain inferences can be drawn whether people think they’re going to vote for certain political parties.”

Sen. Chuck Grassley, R-Iowa, said a new law is unnecessary, noting that there are federal and state regulations already in place against deceptive tactics. Critics also said that one part of the legislation, which would allow private individuals to file lawsuits against people who make false political statements, is unconstitutional.

John J. Park Jr. of the Strickland Brockington Lewis law firm questioned how one would determine the definition of a “true” statement.

“What about statements that are ‘mostly true?’ What about those that are ‘half true?’” Park said in written testimony. He said that the legislation would result in the political parties trying to undermine each other through arbitrary lawsuits.

House insisted the legislation was “narrowly tailored” to avoid such issues. Proponents said that only some states have passed laws against deceptive practices, that there are no criminal penalties under the current federal law and that deceptive speech is unprotected by the First Amendment.