Trump blasts Graham: He 'should respect me'
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Donald TrumpDonald John TrumpFlynn to campaign for Montana GOP Senate candidate Trump considering pardon for boxing legend after call from Sylvester Stallone Decline in EPA enforcement won't keep climate bill from coming MORE early Monday unloaded on Sen. Lindsey GrahamLindsey Olin GrahamGOP sold Americans a bill of goods with tax reform law Republicans divided over legislation protecting Mueller Rand Paul under pressure as Pompeo hunts for votes MORE (R-S.C.), saying his former rival for the GOP presidential nomination should respect him.

Graham, who suspended his own presidential campaign last December, has been a top critic of Trump throughout the 2016 race.

Graham in recent interviews has urged voters to rally around Ted CruzRafael (Ted) Edward CruzCruz's Dem challenger slams Time piece praising Trump Race for Republican Speaker rare chance to unify party for election 32 male senators back Senate women's calls to change harassment rules MORE in the 2016 race, telling NBC's "Meet the Press" on Sunday that Cruz as "made the best case" that he can beat Trump.

Trump on Monday also linked Graham to 2012 Republican presidential nominee Mitt Romney, who last week blasted Trump as a "phony." Trump said both Romney and Graham are "failed" candidates with no credibility.