President Donald Trump cast his fight against illegal migration to the U.S. as a moral struggle, and charged in his second State of the Union address that "partisan investigations" threaten economic progress under his administration.

"We have a moral duty to create an immigration system that protects the lives and jobs of our citizens," Trump said. "No issue better illustrates the divide between America's working class and America's political class than illegal immigration.

"Wealthy politicians and donors push for open borders while living their lives behind walls and gates and guards," he said.