The push to impeach United States President Donald Trump has recently gained momentum after high-ranking House Democrat Ben Ray Lujan voiced his backing for the move.

Lujan is the assistant House speaker and fourth-ranking Democrat in the House. The congressman hails from New Mexico and is also running for Senate in 2020. In a statement on Monday, he said: “I support moving forward with an impeachment inquiry, which will continue to uncover the facts for the American people and hold this president accountable. This is not a position I’ve reached lightly.”

Lujan, like others calling for Trump’s impeachment, cited the Mueller report and added that he believes Trump is putting his personal and political interests ahead of the American people.

More Than Half of House Democrats Support Impeachment

According to an NBC News tally, 125 House Democrats—which is more than half the 235-member caucus—support either impeachment or beginning an impeachment inquiry against the president. Independent Congressman Justin Amash of Michigan also favors starting an inquiry. This means that 126 out of 433 elected officials in the U.S. House of Representatives currently back an impeachment inquiry. Two seats are currently vacant in the House.

Many prominent Democrats in the House have voiced their support for impeachment. These include members of “The Squad”—an informal political grouping made up of Alexandria Ocasio-Cortez (D-NY), Ilhan Omar (D-MN), Ayanna Pressley (D-MA), and Rashida Tlaib (D-MI). Trump has responded to their outspokenness with frequent attacks in speeches and on Twitter.

Tlaib, in particular, has pushed for impeachment before coming into office. She made headlines hours after her swearing-in when she said. referring to Trump: “We’re gonna go in there and we’re going to impeach the motherf****r.”

While House Democratic leaders are hesitant to start impeachment proceedings, a growing number of 2020 Democratic nominees have called on Congress to do so.

Former Housing Secretary Julian Castro was one of the first 2020 candidates to support impeachment. In April, he said it would be “perfectly reasonable for Congress” to move forward with impeachment proceedings. The former HUD secretary’s brother, Congressman Joaquin Castro, is also among 125 House Democrats backing impeachment.

California Senator Kamala Harris has also stated that steps should be taken towards impeachment, adding that the president has obstructed justice.

Vermont Senator Bernie Sanders has also called on the Congress to begin impeachment inquiries to begin. Sanders had previously held the view that starting impeachment proceedings against Trump could help him get re-elected in 2020.

One of the leading 2020 candidates Massachusetts Senator Elizabeth Warren has said “we need to impeach Trump now.”

Frontrunner and former Vice President Joe Biden has not endorsed the idea forthright but has stated he would support an impeachment inquiry if it is proved to be necessary.

Some Democratic party leaders including House Speaker Nancy Pelosi, however, remain opposed to starting impeachment proceedings believing it would help Republicans in the 2020 elections and hurt the Democrats politically.

How Does the Impeachment Process Work?

According to the U.S. Constitution, impeachment proceedings begin in the House, which has presently has a Democratic majority. If the articles of impeachment pass, then the process moves on to the Senate, where the Republicans currently have a majority.

The House must approve articles of impeachment by a simple majority. Since Democrats control the House, if they vote on party lines they could begin impeachment proceedings and vote to impeach him.

Voting in the Senate requires a two-thirds majority to find the president guilty and impeach him. Sixty-seven senators, thus, must vote for impeachment. Since Republicans currently control the Senate, 20 would have to break from party lines—if all 47 Democratic senators vote to impeach Trump.

With elections next year, Democratic leaders may be right to see impeachment proceedings as a potentially costly gamble. The math shows that it would be almost impossible to gain the votes required to impeach Trump. While it will set a precedent and show that the Democrats take the allegations against Trump seriously, the move could also backfire, as the likely defeat of the impeachment push in the Senate may allow Trump—as he did after the release of the Mueller report—to claim that he has been vindicted.