Just a heads up over this holiday weekend: There will be an independent candidate--an impressive one, with a strong team and a real chance. — Bill Kristol (@BillKristol) May 29, 2016

Bill Kristol has been wrong for 2yrs-an embarrassed loser, but if the GOP can't control their own, then they are not a party. Be tough, R's! — Donald J. Trump (@realDonaldTrump) May 29, 2016

The Republican Party has to be smart & strong if it wants to win in November. Can't allow lightweights to set up a spoiler Indie candidate! — Donald J. Trump (@realDonaldTrump) May 29, 2016

If dummy Bill Kristol actually does get a spoiler to run as an Independent, say good bye to the Supreme Court! — Donald J. Trump (@realDonaldTrump) May 29, 2016

Donald Trump on Sunday fired off a series of tweets at Bill Kristol, calling him a "dummy" and an "embarrassed loser" after the Weekly Standard editor, who has been fighting to add an independent candidate to the presidential election late, posted a Twitter message indicating that there will be an "impressive" person launching a campaign.Initially, Kristol tweeted:Within an hour or so, Trump fired back his shots at Kristol, also warning that if Kristol gets an independent to run, conservatives can say "good bye" to nominating the next Supreme Court justice:Kristol has not indicated who the candidate could be, but in early May, he met with 2012 GOP nominee Mitt Romney to discuss potential candidates.However, Romney is no longer working toward the effort, Yahoo News reported recently, saying that the former Massachusetts governor is still motivated to help the "stop Trump" cause, but is no longer contacting people seeking a run.It also was not clear if Kristol was talking about Libertarian Party nominee Gary Johnson . The party nominated the former New Mexico governor as its candidate on Sunday, with former Massachusetts Gov. William Weld as his running mate.Johnson defeated Austin Petersen, the founder of The Libertarian Republic magazine; and anti-computer virus company founder John McAfee in a second ballot for the nomination. He was also the party's nominee in 2012.