JEFFERSON CITY — The Missouri Senate is backing an effort that could make it harder to impeach and oust top officials, less than a year after the state's governor resigned while facing potential impeachment.

Senators behind the proposal say it isn't motivated by the case against former Republican Gov. Eric Greitens. But had the measure been in place last year, House members likely would have been unable to pursue impeachment of Greitens.

The proposal would delete the current eight grounds for impeachment — including two of the causes against Greitens, "misconduct" and "moral turpitude" — and instead limit impeachment to "corruption or crime in office." Under that standard, House members could not have pursued impeachment for allegations of sexual misconduct and campaign finance violations that occurred before Greitens took office in January 2017.

"Had this been the law a year ago, Eric Greitens would still be our governor, despite some pretty egregious behavior," said Democratic Rep. Gina Mitten, who served on the special House investigatory committee that was weighing whether to impeach Greitens.

Greitens resigned June 1, before the panel voted on impeachment, as part of a deal with a St. Louis prosecutor to drop a felony charge alleging that he illegally provided a donor list from a veterans charity he founded to his campaign fundraiser in 2015. He was succeeded by Republican Lt. Gov. Mike Parson.

Prosecutors also decided not to pursue a charge alleging he took and transmitted a nonconsensual photo of a partially nude woman with whom he admitted having an affair in 2015. The woman testified that Greitens slapped her during a sexual encounter, which Greitens denied.

The Senate's proposed constitutional amendment received initial approval earlier this week. It needs a second Senate vote to go to the House and then would be subject to a statewide vote, likely in the 2020 general election. The change would take effect in 2021.

In addition to narrowing the impeachment criteria, the proposal would shift the responsibility for conducting impeachment trials to the Senate instead of judges and would raise the threshold needed to remove an impeached executive branch official.

"It would make it a much more rigorous process," said sponsoring state Sen. Ed Emery, a Republican. "It makes the lasso that you cast to pull in an impeachable offense a little smaller."

Emery added: "I definitely think there was sense that (Greitens) was being mistreated, but I don't think it had any impact on this" proposed constitutional amendment.

Emery said his main objective is to restore the authority for conducting impeachment trials to the Senate, as it had been under an 1875 version of the Missouri Constitution. He has sponsored similar measures in prior years. But to get this year's version out of the Senate Judiciary and Civil and Criminal Jurisprudence Committee, Emery said he had to agree to narrow the grounds for impeachment.

Committee chairman Sen. Tony Luetkemeyer, a Republican attorney, said he was concerned that lawmakers could have used the broader, current criteria to try to remove judges from office for rulings with which they disagreed.

"When you have a generalized, nebulous standard like 'misconduct,' well, what is misconduct?" Luetkemeyer asked rhetorically.

He added: "What I don't want to have happen is somebody reach back into a judge's past — or the past of a statewide elected official — and say something that you did when you were 14 years old, or something that you did whenever you were in college, can then be used and bootstrapped as a basis for removing somebody from office."

Luetkemeyer was not a member of the Legislature during last year's investigation into Greitens, though his wife worked as a legal counsel in Greitens' office.

Mitten, who opposes the measure, said it could give politicians a free pass for misconduct before taking office.

"You could hypothetically get elected in November, rob a bank December 31st, get sworn in a week later — nothing anybody could do about it," Mitten said. "It would not be grounds for impeaching him."

Had Greitens been impeached last year by the House, he would have been tried by a panel of seven judges appointed by the Senate that would have needed five votes to remove him from office.

The Senate's proposal would require a three-quarters vote of the Senate to remove a governor or other elected executive official and a two-thirds vote to remove a judge. That provision is backed by Democratic state Sen. Jason Holsman, who said it would ensure bipartisan support while adding "a layer of protection for those elected officials."

Republicans currently hold a greater than two-thirds majority in both the House and Senate but are just shy of the three-fourths mark.

"If they've done something that rises to the level of impeachment and removal, you would think that it would be near unanimous," Holsman said.