Republican presidential candidate Sen. Marco Rubio, R-Fla., discusses their recently released tax reform plan, Wednesday, April 15, 2015, at the Heritage Foundation in Washington. (AP Photo/Molly Riley)
Republican presidential candidate Sen. Marco Rubio, R-Fla., discusses the recently released tax reform plan, Wednesday, April 15, 2015, at the Heritage Foundation in Washington. (Associated Press) ** FILE **
Texas Gov. Rick Perry gestures as he speaks at the Heritage Foundation in Washington, Thursday, Aug. 21, 2014, about that he would be open to sending U.S. combat forces to Iraq to fight the deadly Islamic state after its attacks on a Christian minority and the beheading of an American journalist and border security. (AP Photo/Manuel Balce Ceneta)
Sen. Ted Cruz, R-Texas answers reporters questions after speaking about energy, Monday, Feb. 10, 2014, at the Heritage Action for America 2014 Conservative Policy Summit at the Heritage Foundation in Washington. (AP Photo/Charles Dharapak)
Sen. Ted Cruz, R-Texas speaks about energy, Monday, Feb. 10, 2014, at the Heritage Action for America 2014 Conservative Policy Summit at the Heritage Foundation in Washington. (AP Photo/Charles Dharapak)
Sen. Ted Cruz, R-Texas speaks about energy, Monday, Feb. 10, 2014, at the Heritage Action for America 2014 Conservative Policy Summit at the Heritage Foundation in Washington. (AP Photo/Charles Dharapak)
Sen. Ted Cruz, R-Texas speaks about energy, Monday, Feb. 10, 2014, at the Heritage Action for America 2014 Conservative Policy Summit at the Heritage Foundation in Washington. (AP Photo/Charles Dharapak)
Sen. Ted Cruz, R-Texas waits off stage as he is introduced before speaking about energy at the Heritage Action for America 2014 Conservative Policy Summit at the Heritage Foundation in Washington, Monday, Feb. 10, 2014. (AP Photo/Charles Dharapak)