WASHINGTON — President Donald Trump said Monday that Supreme Court nominee Brett Kavanaugh has been treated "so viciously and so violently" by Senate Democrats, that he's seen an unnamed Senate Democrat in "compromising" situations — due to alcohol abuse — and that he is still "open" to changing his mind on his pick if a limited FBI investigation turns up new information on allegations of sexual misconduct against Kavanaugh.

Trump's wide-ranging exchange with reporters in the White House Rose Garden — his second press conference of more than an hour in less than a week — covered a vast array of topics, from a planned discussion of the new trade agreement among the U.S., Canada and Mexico to his decision to wait until after the midterm elections to push hard for his border wall to his re-election chances in 2020.

But it was the Kavanaugh nomination, still sitting on a knife's edge, that dominated the question-and-answer session.

The president said that he had told White House counsel Don McGahn to instruct the FBI to conduct further interviews about the allegations against Kavanaugh within the parameters set up by Senate Republicans.

"I want them to do a very comprehensive investigation, whatever that means according to the senators and the Republicans and the Republican majority," Trump said.

Sources familiar with the investigation told NBC News on Sunday that despite the president's tweet earlier in the weekend making the same claim, the limits imposed by the White House counsel’s office on the FBI investigation had not changed. Shortly after the president's remarks on Monday, a senior U.S. official and a separate source briefed on the matter confirmed that the White House has now authorized the FBI to interview anyone it deems necessary — as long as the review is finished by the end of the week.

The New York Times first reported on the change in scope.

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While he said he's keeping an open mind, Trump also rose to Kavanaugh's defense repeatedly Monday — and attacked Senate Democrats on his behalf, even though it is Republican senators who have technically paused the confirmation process by refusing to vote for Kavanaugh until the FBI finishes its investigation.

In particular, Trump took issue with the way Democrats handled their questioning of Kavanaugh at a two-part hearing Thursday when he denied Christine Blasey Ford's allegation that he held her down on a bed, covered her mouth and tried to rape her when they were teenagers in the Maryland suburbs outside Washington.

"I happen to know some United States senators, one who is on the other side who is very aggressive ... I've seen that person in very, very bad situations, somewhat compromising. I think it’s very unfair to bring up things like this,” Trump said of questions about Kavanaugh's drinking in high school and college.

"Even if you were going to bring up some of the subjects that were brought up, they didn’t have to treat him so viciously and so violently as they have treated him," Trump added.

He did not respond to a shouted question asking whether had had any empathy for Ford, the alleged assault victim.

While Trump took issue with Democrats asking about Kavanaugh's drinking habits during the hearing, he also said his nominee was "very strong on the fact that he drank a lot."

In his opening statement, Kavanaugh said that he sometimes had too many beers as a young man but later fought back hard when Sen. Amy Klobuchar, D-Minn., asked if he had ever imbibed enough to lose all or part of his memory on a given night.

"Have you?" he fired back, an outburst for which he later apologized.

Kavanaugh's past drinking habits have become an issue in his confirmation process for two reasons: some senators wonder if heavy drinking could affect his ability to recall the attack Ford said he committed and some senators believe he was evasive — if not outright lying to Congress — about his alcohol consumption during the hearing.

Trump addressed a variety of topics related and unrelated to the confirmation process. He appealed to Americans to reject Democrats at the polls in November because the party has resisted his efforts to build a border wall between the U.S. and Mexico.

"I really believe that the people of our country want the wall and they want border security," he said. "They don’t want open borders like the Democrats want. They don’t want crime pouring into our country. They don’t want MS-13 pouring into our country."

And, he added, "the Democrats don’t want to take care of our law enforcement, and the Democrats don’t want to take care of our military."

But Trump acknowledged that many in his own party believe his rhetoric and policies on immigration could harm Republicans. He cited that as his reason for waiting to confront Congress on the border wall until after the midterms.

"I have some very fine people who are running in close races," he said of Republicans who could have been hurt if he had shut down the government over Congress' reluctance to pass full funding for his wall. He also noted that he disagrees with candidates and strategists who thought that was a bad idea.

"I happen to think it would be good for them," he said.