That's a question many conservative fear answering.
Everyone -- from extreme Left to extreme Right -- supports legal immigration and opposes illegal immigration.
The Left would say, yes legal immigration only. All Third World migrants should be legal. But white South Africans, and others who would empower "white supremacy" should be illegal.
Some conservatives would say, only skilled immigrants should be legal.
More nationalist conservatives might say: No skilled immigrants if they compete with Americans who already have those skills (e.g., not visas for Indian tech workers).
Some businesses might say: Unskilled laborers should be legal.
Union workers might say: Unskilled laborers should be illegal.
But to simply say "legal yes, illegal no" is to say nothing.
Arguing with bags of hammers leads nowhere.