What's behind the immigration issue?
Really? Forget the "public debate", everyone knows the general public's opinion has no real bearing on policy decisions. We're only brainwashed to accept or deny a decision that's already been made, by people way above our influence level..
Is it about cheap labor? Votes? Allowing people the right to build a better life? All that tax money that can't be claimed at retirement? Something else?
Who keeps pushing for and against it?
Personally, I think the Republicans are as supportive of foreign immigrants as the Democrats are.. You can see this by how they employ undocumented labor, the same as their left wing counterparts.