LAS VEGAS — President Donald Trump embraced hard line immigration policies as a centerpiece of the Republican Party’s midterm campaign strategy Saturday, a risky move as he stumped for an endangered GOP senator in this rapidly-diversifying swing state.Defending the work of border patrol agents who have come under scrutiny for taking migrant children away from their families as part of his administration’s family separation policy, Trump said Democrats “just want to use this issue — and I like the issue for (the) election, too.”“Our issue is strong borders, no crime,” Trump said in an address to the Nevada Republican Party’s state convention.