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

Senate Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellConservatives wage assault on Mueller report Overnight Energy: Interior reverses decision at heart of Zinke criminal probe | Dem divisions deepen over approach to climate change | GM to add 400 workers to build electric cars Trump: Green New Deal 'the most preposterous thing' and 'easy to beat' MORE (R-Ky.) is sending a clear warning to Donald TrumpDonald John TrumpMueller report findings could be a 'good day' for Trump, Dem senator says Trump officials heading to China for trade talks next week Showdown looms over Mueller report 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 ClintonIf Mueller's report lacks indictments, collusion is a delusion Conservatives wage assault on Mueller report The wisdom of Trump's lawyers, and the accountability that must follow Mueller's report 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.