Former Republican presidential campaign strategist Stuart Stevens had some key advice for Vice President Kamala Harris as she tries to drag down former President Donald Trump and map out her path to victory in the fall. Stevens, who ran the Mitt Romney presidential campaign in 2012, discussed the key issue that Harris needs to go after during a Politico roundtable alongside Robby Mook and Patti Solis Doyle, who ran previous presidential campaigns for Hillary Clinton. “If I were on the Harris campaign, I would attack Donald Trump on his record with immigration,” said Stevens. “It was a total fa…