The political showdown over the Russia investigation that could reshape the remainder of President Donald Trump's term began in earnest Saturday even before the special counsel's conclusions were known to the public, as Trump allies claimed vindication while Democrats demanded transparency and vowed to intensify their own probes.

Trump and his attorneys and aides were clouded by uncertainty because they did not yet know the contents of Robert Mueller's report, which Attorney General William Barr and a small coterie of Justice Department officials spent Saturday privately reviewing.

Ensconced for the weekend in Palm Beach, Florida, Trump exuded optimism while playing golf, lunching at the clubhouse and chatting with friends. At the urging of his advisers, he also exhibited uncharacteristic caution, refraining from publicly crowing that the "witch hunt" was over or declaring victory prematurely. Asked mid-Saturday to evaluate the president's mood, White House spokesman Hogan Gidley said simply, "He's good."

The Trump team clung to hopeful signs - such as word from the Justice Department that there would be no more indictments from Mueller's team - that the president could end up exonerated after a nearly two-year investigation of Russia's interference in the 2016 presidential election.

But there was also widespread recognition within the Trump orbit that the Mueller report could still contain damaging information for the president - and that his legal troubles are far from over, with separate investigations into Trump's business, inaugural committee and conduct continuing apace in New York and on Capitol Hill.

Rudy Giuliani, one of Trump's personal attorneys, said he was in a "watch and wait" mode and had been urging the president to "keep your powder dry."

"The information that has been revealed publicly, particularly no further indictments, has been helpful," Giuliani said. But, he added, "until you read the report, you don't know exactly what it entails. . . . My message is: We've all waited this long. Let's just await the reading of what's disclosed, and then we can have proper final reactions. There's too much assuming going on, on the other side, and we shouldn't fall into that trap."

Still, the contours of the political battles ahead took form. The mood among Democrats was tense and urgent, with expectations running high that Mueller's complete report could be explosive and spark a reckoning for Trump. Party leaders called for the report to be released in full, along with the underlying documents.

Americans "deserve the truth, to know the truth," House Speaker Nancy Pelosi, D-Calif., said Saturday afternoon on a conference call with caucus members. "Transparency is the order of the day."

Rank-and-file Democrats worried to House leaders that the Justice Department's independence could be threatened, according to several aides involved in those talks, while Pelosi tried to fend off - for now, at least - calls within her party to seek Trump's impeachment.

"I think that day will come," Rep. John Lewis, D-Ga., told MSNBC's Joy Reid on Saturday. "I don't think he's legitimate. I said it back at the end of the election. I still believe that today."

On the campaign trail, Democratic presidential candidates called for full transparency from the Justice Department.

"We really need a full accounting of what happened," Pete Buttigieg, mayor of South Bend, Indiana, told a breakfast crowd in Greenville, South Carolina. He added, "It may well be the case that the only appropriate response is impeachment, but to me the most decisive way to put an end to Trumpism is for it to be defeated massively at the ballot box."

Among Republicans, meanwhile, the calls for caution from Trump's attorneys did not seem to reach the ears of his allies, who took a victory lap on the president's behalf.

"This is a vindication for the president and his family that after one year, 10 months and six days the Mueller report is concluding something which we already knew, which there was no collusion between the Trump campaign and the Russians," said Corey Lewandowski, Trump's former campaign manager.

Stephen Bannon, Trump's former chief strategist, wrote in an email that the president would "weaponize Mueller report to bludgeon Democrats. Expect him to come 'off the chain.' "

There was a defiant streak throughout conservative media. On Breitbart, headlines read "Leftists cope with Mueller report bust" and "MSNBC-onspiracy!" And on the Sirius radio program "Breitbart News Saturday," upbeat tracks from the "Ghostbusters" and "Rocky" soundtracks played as a parade of Trump allies called in with commentary.

A feeling of relief set in among the many Trump associates who had spent hours being questioned by Mueller's investigators, including former campaign official Michael Caputo.

"My family has lost everything and now we're starting over, but I awoke today optimistic for us and for our nation," Caputo said.

On Friday evening, after Mueller gave his report to Barr, Trump was at his Mar-a-Lago Club and in unusually good spirits, according to people who interacted with him. Cable news shows were abuzz with reports about the Mueller probe, but Trump was not seen watching much television. Rather, he sat at his usual table on the patio for dinner and to celebrate his son Barron's 13th birthday with his wife, Melania, and Donald Trump Jr. and his girlfriend, Kimberly Guilfoyle.

Trump Jr., who had been vacationing at Mar-a-Lago all week with his children, was on a boat fishing when the Mueller news broke Friday. The president's son, who had come under scrutiny for the 2016 meeting he arranged at Trump Tower with a Russian lawyer promising dirt on Hillary Clinton, responded by tweeting a picture of himself and his boys holding up the fish they caught and then retweeting pro-Trump reactions.

President Trump left the patio for about an hour Friday night to attend a Republican Party fundraising dinner in Mar-a-Lago's ballroom, where the crowd chanted "Lock her up!" after one of the featured speakers, Sen. Lindsey Graham, R-S.C., called for an investigation of "both sides" - reflecting the desire of Trump supporters to go after Clinton, the defeated 2016 Democrats nominee.

Late in the evening, the president returned to the patio and appeared loose and upbeat, nodding and smiling as club members and other friends approached him at the table. Although nobody quite knew what the Mueller report said or what might happen next, people still cheered Trump. He in turn told several guests that he was proud of his accomplishments in office but did not speculate or engage in detailed discussion about the Mueller probe, according to people who were present.

At one point, White House lawyer Emmet Flood joined for a few minutes to talk with the president, as did Graham, who said he urged Trump to "listen to your lawyers."

"He keeps saying he didn't do anything with the Russians, and I said, 'Well, there's only one person that can really clear the air here, and that's Mueller, and he's been able to do his job and we'll see here in a day or two what he found,' " Graham said in an interview Saturday.

Typically, Trump is accompanied by only a small staff entourage, sometimes with mid-level aides, on his weekend jaunts to Florida. But on Friday, several senior White House officials, including chief of staff Mick Mulvaney and press secretary Sarah Sanders, flew with him to Florida - in part so Trump would be surrounded by people he knows and trusts and therefore be less likely to do something rash, according to two people close to the president who requested anonymity to reveal internal details.

Trump agreed with his aides to be restrained in his public comments about the Mueller report until he gets a full briefing on its findings, which could occur as early as Sunday. Reminded that the president's inclination has been to break the shackles his aides place on him by tweeting his feelings, one senior administration official replied, "The stakes are higher."

On Saturday, Trump spent much of the day at the Trump International Golf Club in nearby West Palm Beach. Trump golfed and spent time with musician Kid Rock, according to an administration official and the musician's Instagram page, where he posted a picture posing with the president.

And there was a celebratory mood among the Trump fans - "my bridge people," as the president calls them - who gathered near a bridge to cheer the presidential motorcade as it traveled to and from Mar-a-Lago, despite not knowing what the report says.

"I'm relieved that it's finally out and it vindicates our president," Paula Magnuson said. "Hopefully the Democrats will let it go now."

Trump has told confidants he has not known Barr for long and that he cannot predict how the attorney general, who was sworn in only last month, will handle the situation. But the president also has said he is glad Barr is in charge and not former attorney general Jeff Sessions, and he has reiterated that his attorneys have told him Barr is fair, according to advisers who have spoken with him.

With little new information emerging Saturday, officials said Trump's attorneys impressed upon the president to take a hands-off approach and to be patient with Barr - waiting for him to share Mueller's conclusions on his own timetable and not to contact the attorney general or press for an update.

"He's not going to engage a lot until he gets more information," said David Bossie, Trump's former deputy campaign manager.

That is the plan, but as those who work for him readily acknowledge, Trump rarely sticks to plans.

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The Washington Post’s Meagan Flynn and Lori Rozsa in Palm Beach, David Weigel in Greenville and Colby Itkowitz in Washington contributed to this report.