WASHINGTON -- "Stop whining," President Barack Obama rebuked Donald Trump on Tuesday, speaking out as seldom before on next month's election and chiding the Republican for sowing suspicion about the integrity of America's presidential vote.
Obama also accused Trump of cozying up to Russia's Vladimir Putin to a degree "unprecedented in American politics."
The president said Trump's intensifying pre-emptive warnings about voter fraud are unheard of in modern politics. The rhetoric is not based on any evidence, Obama said, but is simply aimed at discrediting the outcome before the first votes are counted.
"You start whining before the game is even over?" Obama said at a Rose Garden news conference. "If whenever things are going badly for you and you lose you start blaming somebody else -- then you don't have what it takes to be in this job."
Campaigning in Colorado, the GOP candidate repeated his assertions about "corrupt" elections but did not respond directly to the president. Trump vowed to "drain the swamp" in Washington, and for the first time promised to push for a constitutional amendment to impose term limits on all members of Congress.
The president's remarks came as Trump and his Republican allies look for ways to regain momentum after a damaging few weeks in the campaign. Heading into the third and final debate Wednesday night, Trump is trailing in the polls and running out of time for a comeback before Nov. 8.
Obama waded into the race to elect a successor, speaking at the White House where he was hosting his final state visit. Italy's Prime Minister Matteo Renzi at his side, the president initially said he would pull his punches when it came to politics, respecting the official setting. But when he was asked about Trump's rhetoric, he hardly held back.
"I would invite Mr. Trump to stop whining and go try to make his case to get votes," he said.
The GOP candidate has ramped up warnings about potential fraud. That's drawing criticism not only from Democrats but from his own party, particularly the state and county officials who run local elections, who fear the rhetoric will give losers license to dispute any results.
"They even want to try and rig the election at the polling booth, where so many cities are corrupt and you see that and voter fraud is all too common," Trump said at a rally in Colorado Springs.
Independent studies and election officials in both parties say they see no evidence that voter fraud -- individuals impersonating others to cast ballots -- is a widespread problem.
Asked about Trump's claims on Tuesday, running mate Mike Pence dodged and suggested Trump's point actually was about the "overwhelming bias in the national media."
Pence spoke after touring the burned-out offices of the Republican Party in Hillsborough, North Carolina. The GOP office was firebombed over the weekend in what Pence called an "act of political terrorism." Trump pointed at Clinton supporters, but Pence did not assign blame. Police are investigating.
Clinton held no public events Tuesday while she prepared for the debate. She has her own troubles and is certain to be asked about the latest revelations involving her use of a private email server during her time as secretary of state.
New FBI documents released Monday revived questions about whether she received classified information and whether State Department allies sought to protect her from criticism over the email arrangement.
The FBI notes show a State Department official asked the FBI to lower the classification of a sensitive email found on her server. The email was related to the attack on the U.S. compound in Benghazi, Libya.
The documents revealed discussion of a "quid pro quo" in trying to get the email reclassified, though it's not clear who first raised the issue. Both State and FBI officials deny any bargaining took place, and the email was not declassified.
Trump called it an "elaborate and deliberate coverup" and called for the State Department official, Undersecretary for Management Patrick F. Kennedy, to be fired.
The Republican is hoping to turn the conversation away from the allegations of sexual misconduct that partly dominated his last debate against Clinton.
In an interview with Fox News aired Tuesday, Melania Trump vouched for her husband and blamed the accusations on political rivals: "They want to damage the presidency of my husband, and it was all planned, it was all organized from the opposition."
Her comments carried echoes of Clinton's allegations of a "vast right-wing conspiracy" organized to raise similar allegations against her husband two decades ago. Trump notably tried to revive Bill Clinton's history by inviting his accusers to the last debate. His guest list for Wednesday's faceoff in Las Vegas includes Pat Smith, whose son, Sean Smith, was killed in the attack in Benghazi. Smith was a featured speaker at the Republican National Convention, where she delivered an emotional speech blaming Clinton for her son's death.
As for Russia, Obama accused Trump of showering praise and modeling his policies on Russian President Putin to a degree that is "unprecedented in American politics."
He said he has been "surprised and troubled" by Republican lawmakers who he said are echoing their presidential nominee's positions. Trump has praised Putin as a strong leader and criticized Obama and Clinton for Washington's deteriorating relationship with Moscow.
In an interview Monday, Trump said Russia "can't stand" either Democrat. He promised a closer relationship with Putin, if elected, starting with a possible meeting before Inauguration Day.
Associated Press writers Jill Colvin in Colorado Springs, Colorado; Michael Biesecker and Eric Tucker in Washington. Hennessey reported from Washington.