I do not believe that immigration harms the country on the whole.  Immigrants may become criminals, but not at a rate that diverges from the general population.  The U.S. is able to absorb those people who want to live in the U.S..  I believe that these people in general contribute more to our society than what some may take out of it in terms of social welfare benefits.  Finding a reasonable way to allow those who have entered illegally would be the morally right thing to do.  Maintaining both border security and accommodating the demand to immigrate to the U.S. from countries to our south would eliminate this as a political issue.