Rep. Al Green (D., Texas) said on Saturday that if Democrats don't begin impeachment proceedings against President Donald Trump, "he will get re-elected."

Green, who has called for Trump's removal from office since 2017 and introduced articles of impeachment that year, told MSNBC that he dismissed the idea that impeaching Trump could help him politically.

"I'm concerned if we don't impeach this president, he will get re-elected. If we don't impeach him, he will say he's been vindicated," Green said. "He will say the Democrats had an overwhelming majority in the House and they didn't take up impeachment. He will say that we had a constitutional duty to do it if it was there, and we didn't. He will say he's been vindicated."

Green added he and fellow House Democrats face a constitutional crisis on the question of impeachment.

.@RepAlGreen: "I’m concerned if we don’t impeach this president, he will get re-elected. … We must impeach him." pic.twitter.com/3cwG7eFIdy — Tom Elliott (@tomselliott) May 5, 2019

"When the chief executive office of the president of the United States refuses to comply with subpoenas and says he will order others to do so, this creates a constitutional crisis, but this isn't the genesis of it," Green said. "It started when the president decided he would fire [former FBI Director James] Comey for his failure, pardon me, as a result of his desire not to be investigated. When he decided to do this and went on TV, on national TV at primetime and indicated he was thinking about this Russia thing, that was the genesis of it. We have a constitutional crisis."

It doesn't matter if impeachment proceedings increase Trump's chances at re-election, because impeachment will ensure the integrity of Congress, Green said.

"We must impeach this president. If we don't, it's not the soul of the nation that will be at risk only, it is the soul of the Congress that's at risk. Congress has a duty, a responsibility and obligation that only it can fulfill. No one else can. No other entity can. It is Congress that will have to act," he said. "If we allow political expediency to trump moral imperative, we will have created a shameful situation of this Congress that will never live down, history won't be kind to us. We must impeach him."

The question of impeachment has divided Democrats, with House leadership rejecting it. A new Quinnipiac poll shows 66 percent of Americans do not favor impeachment.