McConnell: Trump needs to act like a 'serious candidate'

Senate Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellThe Mueller report is a deterrent to government service Senate Republicans tested on Trump support after Mueller Anti-smoking advocates question industry motives for backing higher purchasing age MORE (R-Ky.) is sending a clear warning to Donald TrumpDonald John TrumpTrump calls Sri Lankan prime minister following church bombings Ex-Trump lawyer: Mueller knew Trump had to call investigation a 'witch hunt' for 'political reasons' The biggest challenge from the Mueller Report depends on the vigilance of everyone MORE, arguing the presumptive presidential nominee needs to pivot and act like a "serious candidate." 

“It’s no secret that he’s struggling,” McConnell told Kickass Politics' Ben Mathis during a podcast posted Friday. “I’ve endorsed him because he’s earned the nomination, but he needs to start acting like a serious candidate for president if he wants to win the election.”
The Senate Republican leader added that Trump has made "a number of very significant gaffes that have had him moving down in the polls." 
Trump has spent weeks being chastised by lawmakers — including those in his own party — after he said a federal judge overseeing lawsuits against Trump University was biased because of his Mexican heritage. 
Trump's campaign finished May with just $1.3 million in the bank. McConnell, referencing the campaign finance report, added, "It’s not much money in there." 
Though McConnell frequently sidesteps questions on Trump during his weekly press conferences, he hasn't shied away from calling on Trump to stick to the issues rather than throwing rhetorical barbs. 
While doing a steady stream of interviews earlier this month to promote his book "The Long Game," McConnell, known for being strategic and tight-lipped, provided increasingly sharp criticisms of his party's standard-bearer.
He added during Friday's podcast that "look, I want him to change and I want him to win, because I know what Hillary ClintonHillary Diane Rodham ClintonIt is wrong to say 'no collusion' 10 factors making Russia election interference the most enduring scandal of the Obama era And the winner of the Robert Mueller Sweepstakes is — Vladimir Putin MORE will do, four more years just like the last eight." 
McConnell is performing a balancing act with Trump as he works to defend 24 Senate seats this fall, including a handful in states that voted for President Obama.
McConnell's comments, part of a longer interview about his book, were first reported by BuzzFeed.