Republican rivals Ted Cruz and Marco Rubio sparred at length about the issue of immigration during Tuesday night’s GOP presidential debate. Backed into a rhetorical corner by Rubio, Cruz did not explicitly rule out legalizing illegal immigrants.

Cruz argued that during the Senate’s 2013 immigration fight, Rubio sided with President Obama and Sen. Chuck Schumer, D-N.Y., while Cruz worked with Iowa Rep. Steve King and Republican Sen. Jeff Sessions of Alabama. Cruz also quipped that he would build a wall that works and get Donald Trump to pay for it.