The independent senator will enter the Democratic fray Thursday to challenge Hillary Clinton.
Two new polls show the Wisconsin governor leading his possible Republican rivals.
'16 GOP hopeful says there are "root, cultural causes" for violence but "there is no excuse."
Clinton tweeted her support to those going before the Supreme Court today.
“Senator Rubio is a longtime leader in the taxpayer movement," Norquist said.
Democrats are quickly learning the perils of having a de facto nominee in Clinton.
Democrats say the incident has thrust Rep. Elijah Cummings into a leadership role.
Rep. Steve Knight told an immigration protester, "If you touch me again, I'll drop your ass."
The 2016 candidate also criticized the U.S. campaign that ousted Moammar Gadhafi.