http://www.whitehouse.gov/issues/immigration
Actually I think immigration isn't bad for USA.. it can make the global world and makes rich country. But the problem is illegal immigration. The scale of illegal immigration in to U.S. is massive. More than 10 million undocumented people from different country are currently living in the United States.
Immigration Reform and Control Act of 1986 drastically increased the number of immigrants allowed into the United States. The United States has mass illegal immigration because successive Congresses and Presidents have decided they want it. From nowadays, it has to fixed and make a law for immigration.
https://www.numbersusa.com/problems
To solve this problem we are supposed to follow these forms.
Reform the legal immigration system.
Make immigration more responsive to the needs of the economy.
Reinvigorate interior enforcement measures.
Enhance border security efforts.Recognize state and local authorities as responsible partners.
http://www.heritage.org/research/reports/2013/01/immigration-reform-needs-problem-solving-approach-not-comprehensive-legislation