Sens. Heidi Heitkamp (D-N.D.) and Joe Manchin III (D-W.Va.) (Melina Mara/The Washington Post)

A group of Democratic senators is set to huddle with a top White House official to discuss potential changes to the Republican tax plan Tuesday, according to people familiar with the meeting.

Marc Short, the White House director of legislative affairs, and Gary Cohn, director of the National Economic Council, are set to meet at the U.S. Capitol with at least eight Democrats, Sens. Joe Manchin III (W.Va.), Heidi Heitkamp (N.D.), Claire McCaskill (Mo.), Joe Donnelly (Ind.), Jon Tester (Mont.), Ron Wyden (Ore.), Thomas R. Carper (Del.) and Sherrod Brown (Ohio), according to multiple aides who spoke on the condition of anonymity to speak frankly about private meetings.

What, if any, substantive change to the emerging proposals might come out of the meeting is unclear — but it will allow the White House and these moderate Democrats to claim that they are at least trying to forge bipartisan consensus. The meeting came at the request of Manchin, who spent the last few days organizing the guest list, aides said.

So far, Republicans have controlled debate over what is now their marquee legislative goal, understanding that failure to enact changes to the nation’s tax code this year could spell doom for GOP congressional incumbents at the ballot box next year. Tuesday’s meeting is likely to upset top Senate Republican leaders, who are eager to keep Democrats out of the conversation in hopes of making their lack of cooperation a campaign issue next year.

Twenty-five Democratic senators face reelection in 2018 — a daunting task for the minority party eager to make gains in the chamber. Donnelly, Heitkamp, Manchin, McCaskill and Tester are what top Democrats call “the big five” — five moderates representing states that President Trump won in 2016 who are likely to face difficult reelection fights. Brown and Carper are also up for reelection next year.

Despite being shut out of the tax debate, those attending Tuesday’s meeting have insisted they are eager to reach accord with Republicans.

That’s why the White House has made cautious but calculated outreach to Manchin, Heitkamp, Tester and Donnelly. Heitkamp and Donnelly even flew aboard Air Force One and appeared with Trump at tax cut rallies, where he needled them in front of supportive crowds, hoping they will sign onto GOP proposals. Trump made a similar trip to Missouri and McCaskill has been part of meetings with the president. She also attended a dinner hosted by Ivanka Trump and Jared Kushner on the subject.

Manchin has also huddled with Vice President Pence about potential lines of agreement. The outreach continued a few weeks later over dinner at the White House with Trump and other Democrats.

At a more recent White House dinner, Brown presented Trump with two proposed tax bills. One would expand access to the Earned Income Tax Credit and the Child Tax Credit, while the other would give tax credits to companies that pay workers at least $15 an hour and offer health-care and retirement benefits.

The talks between administration officials and Democrats will come as House Republicans continue public hearings on their tax reform plan and as the Senate Finance Committee puts the finishing touches on a plan they’re likely to unveil as early as Thursday. Wyden is the top Democrat on the Senate Finance Committee.