John Derbyshire wrote that

Scott Walker also said he wanted a “legal immigration system that gives priority to American working families and wages”—which he said later on Hannity meant lower numbers

Here's what Walker said in the debate:

"There's international criminal organizations penetrating our Southern base borders, and we need to do something about it. Secure the border, enforce the law, no amnesty, and go forward with a legal immigration system that gives priority to American working families and wages."

Here's the Hannity clip, starting at 1:40 in between some stuff about Planned Parenthood and Israel. As he says, he's "fairly unique" among Republican candidates in wanting to control legal immigration.

Scott Walker on GOP debate, abortion and Planned Parenthood

Aug. 07, 2015 - 3:55 - Wisconsin governor and Republican presidential candidate on 'Hannity' #GOPDebate