The Biden administration issued a policy position Tuesday in support of D.C. statehood, forcefully backing legislation to make the District the 51st state ahead of a House vote scheduled for Thursday.

Noting Washington’s “robust economy, a rich culture, and a diverse population of Americans from all walks of life,” the administration said the proposed State of Washington, Douglass Commonwealth would “make our Union stronger and more just.”

“For far too long, the more than 700,000 people of Washington, D.C. have been deprived of full representation in the U.S. Congress,” the administration wrote. “This taxation without representation and denial of self-governance is an affront to the democratic values on which our Nation was founded.”

It is the strongest backing the statehood cause has ever received from the White House.

Presidents Bill Clinton and Barack Obama expressed vague support for statehood while in office, but they did not take any action to advance legislation to make it happen.

The House first voted on D.C. statehood during the Clinton presidency, in 1993, and more than 100 Democrats joined Republicans in opposing the bill.

Nearly two decades later, D.C. statehood has become a central voting rights and civil rights cause for the Democratic Party. Almost every House Democrat has co-sponsored Del. Eleanor Holmes Norton’s statehood bill, H.R. 51, which passed the chamber for the first time last year on a party-line vote, and will be voted on again on Thursday.

The legislation does not have enough votes to pass the closely divided Senate, where the filibuster means it would need the support of 60 senators to advance.

But Majority Leader Charles E. Schumer (D-N.Y.) has promised to bring the measure to the floor.

The House bill passed out of the Oversight and Reform Committee last week, again on a party-line vote. It was being debated Tuesday by the House Rules Committee, where lawmakers will consider amendments and establish rules of procedure ahead of the floor vote Thursday.

Republicans continued to argue that statehood was unconstitutional and question the District’s financial readiness to become a state.

During a GOP news conference on Tuesday, Rep. Nancy Mace (S.C.) said that not enough people are living in the city to qualify it as a single congressional district, apparently unaware that D.C. has more residents than Wyoming and Vermont, each of which has two senators and one House member.

The creation of the federal district is enshrined in the Constitution. Democrats say that turning the bulk of the city into the 51st state would be in keeping with the Constitution, because Norton’s bill would not eliminate the district, but would only change its borders.

Under her measure, a two-square-mile federal enclave would remain — containing federal buildings and monuments — while the surrounding residential and commercial neighborhoods would become a state.

“The Administration looks forward to working with the Congress as H.R. 51 proceeds through the legislative process to ensure that it comports with Congress’ constitutional responsibilities and its constitutional authority to admit new states to the Union by legislation,” the White House wrote.

The statement called on Congress “to provide for a swift and orderly transition to statehood for the people of Washington, D.C.”

Last year, with Republicans in control of the Senate and the Trump White House opposing statehood, the bill died after the House vote.