The Republican Party is dividing over presumptive nominee Donald Trump.

Senator Lindsay Graham is the latest. CNN quotes him saying he won't vote for either Trump or Hillary Clinton. Yesterday, House Speaker Paul Ryan said he’s not ready to support Trump as the Republican nominee.

Trump responded to Ryan's reluctance by saying he’s, "not ready to support Speaker Ryan's agenda. Perhaps in the future we can work together and come to an agreement about what is best for the American people."

The father and son former Presidents Bush say they won't attend the July convention. Past nominee Mitt Romney also says he'll skip it. Is this a preview of how GOP voters will split? What does that mean for the party's chances in down-ballot races? Could it cost Republicans the Senate?

Guests:

Paris Dennard, Republican political analyst and former staffer for President George W. Bush and the Republican National Committee; currently serving as the legislative director of the Thurgood Marshall College Fund

Shane Goldmacher, political reporter at POLITICO covering the 2016 presidential race; he tweets @ShaneGoldmacher

Lisa Mascaro, Congressional reporter, Los Angeles Times