WASHINGTON -- Sean Spicer's visit to Trump Tower on Election Night looms large as a federal judge decides whether to end Republican National Committee's 35-year restriction on its voter activities in a case that began with a New Jersey election.

A court-sanctioned agreement limiting GOP activities targeting minority voters, known as a consent decree, is scheduled to end Friday unless U.S. District Court Judge John Michael Vazquez decides to extend it.

Before he rules, Vazquez agreed to let Democratic National Committee lawyers question Spicer, the former White House press secretary, about his Election Night activities.

The case comes as President Donald Trump claimed without evidence that millions of people voted illegally in the 2016 election and formed a commission to examine voter fraud, which studies have shown is virtually non-existent.

"I would not have worried about the RNC engaging in conduct that would count as voter suppression," said election law expert Rick Hasen, a professor of law and political science at the University of California, Irvine. "But with Trump leading Republicans, who knows? He's made unfounded claims of massive voter fraud a key part of his political strategy. So I'm worried."

U.S. Sen. Cory Booker, D-N.J., who called Trump's Presidential Advisory Commission on Election Integrity "a thinly veiled voter suppression effort" and has introduced legislation to end the panel, said the consent decree should continue.

"There are voter suppression efforts going on all across the country," Booker said. "We definitely see a climate and a president who's willing to incite people to do a lot of very dangerous things. The consent decree gives certain protections and assurances that are really needed going forward."

At the time of his visit to Trump Tower last November, Spicer was working for the Republican National Committee. He later became White House press secretary, resigning his post in July.

During the election, Democrats failed to convince Vazquez that the Trump campaign was working in concert with the GOP's national committee and therefore the candidate's calls for poll watchers in minority areas violated the consent decree. Such coordination is not allowed.

They are hoping that questioning Spicer about his Trump Tower visit will provide the proof they need that the presidential campaign did coordinate with the Republican Party on voter issues and therefore the consent decree should be extended.

Republican National Committee spokesman Ryan Mahoney said no violations occurred.

"The RNC has been in full compliance with the consent decree," Mahoney said. "As the judge has made clear, the DNC has failed to find any evidence of a violation despite repeated efforts to do so. We are literally 100 percent confident that this time will be no different."

The limits were imposed after the 1981 New Jersey gubernatorial election, narrowly won by Thomas H. Kean, in which the state Republican Party reportedly targeted heavily minority communities that tend to support Democratic candidates.

Trump and Republicans have championed the use of voter-identification laws that have been found to discriminate against minority voters who normally support Democratic candidates.

The type of in-person voter fraud such laws are designed to protect against is extremely rate, studies have shown.

For example, after the 2016 election, reviews by election officials in California, North Carolina, Ohio and Tennessee found just 324 potential fraud cases out of more than 29 million ballots cast, or one-thousandth of 1 percent, according to the Center for Election Innovation and Research in Washington.

And Justin Levitt, a professor at Loyola Law School in Los Angeles, found just 31 possible fraud cases out of more than 1 billion votes from 2000 through 2014.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.