SALT LAKE CITY — One man is an island: Sen. Mitt Romney of Utah. The 72-year-old former Republican presidential nominee has isolated himself from Republicans in the Senate, in his home state and across the country by occasionally — but strongly — criticizing President Donald Trump, including the president's efforts to enlist the aid of foreign governments to probe a leading political opponent. "By all appearances, the President's brazen and unprecedented appeal to China and to Ukraine to investigate Joe Biden is wrong and appalling," Romney tweeted earlier this month. In recent weeks, the senator's acts of rebellion against the...