President Trump’s commission on voter fraud and suppression likely will hold its first meeting next month after a “painstakingly” slow vetting of its members, one of the panel’s co-chairmen said Tuesday.

Kansas secretary of state Kris Kobach said he expects the commission to meet in Washington sometime in the second half of July to begin its work. Some commission members have complained of not having heard anything about a timetable since being appointed weeks ago.

“The wheels have been turning for several months now. It’s just the process of getting members through the clearance hurdles is painstakingly long,” Mr. Kobach told The Washington Times. “We have almost all of our commissioners through the approval process, but we still have a few more remaining.”

Mr. Trump created the Election Integrity Commission in May after claiming that former Secretary of State Hillary Clinton received millions of illegal votes from noncitizens to help her to win the popular vote, while she lost to Mr. Trump in the Electoral College, which actually determines the presidency.

The bipartisan commission, which will have 12 to 15 members, is co-chaired by Vice President Mike Pence. The panel includes state elections officials such as Maine Secretary of State Matt Dunlap, former Arkansas state Rep. David Dunn, Indiana Secretary of State Connie Lawson, and Maryland Deputy Secretary of State Luis Borunda.

Mr. Kobach said commission staff who are employees in the executive office of the president have been gathering election data and preparing for the first meeting while the background checks of commission members continue.

“What many people may not recognize is that, when you’re appointed to a presidential commission, it’s as if you are appointed to a job in the administration,” Mr. Kobach said. “You have to go through the same FBI and IRS background checks.”

As the commission slowly gears up, opponents are working to discredit and counter it. The Lawyers’ Committee for Civil Rights Under Law said it has started using its “election protection hotline” (866-OUR-VOTE) to accept complaints about the president’s commission or “any resulting voter suppression” from the panel’s actions.

“We will not stand by idly while the president and his administration move forward with a commission that has no meaningful mandate and that promotes a false and dangerous narrative that vote fraud is widespread,” said Kristen Clarke, the group’s president. “We have grave concerns that the commission’s activities will stoke fear in communities and encourage officials to undertake action that may suppress the rights of minority voters.”

Mr. Kobach called the group’s accusations “complete and utter nonsense.”

“How would a commission studying statistics in any way affect the decision of a minority voter to vote in some future election?” he said. “They’re a left-wing organization and they oppose photo ID, and they’re opposed to election security measures generally.”

Former House Speaker Newt Gingrich said Tuesday that congressional committees investigating Russian hacking in the presidential election should call former President Barack Obama to testify about any steps he took to stop it.

Mr. Kobach said he doesn’t believe the commission will ask for Mr. Obama to testify.

“Probably not, because I’m not sure that President Obama has any information or expertise on the issue of voter fraud,” he said. “There are certain agencies that do — of course the Department of Homeland Security has data, and the Department of Justice may have information. But I have no reason to believe that President Obama is personally familiar with any of this information. His comments in the past have suggested that he may not be aware of it.”

One part of the commission’s work will be to compare the federal government’s database of noncitizens — green card holders, temporary visa holders and illegal immigrants who’ve been arrested, for example — and check them against state voter registration rolls.