Nebraska Senator Ben Sasse says he will not back Republican frontrunner Donald Trump for president, the highest-ranked elected party member to do so. He says he is “frustrated and saddened” and will look for a third option if Trump wins the Republican nomination. The colorful campaign of Trump, who has already won three of the four early voting states, has divided Republicans, BBC reported. The brash billionaire is leading almost all of the 11 states voting for their presidential candidates on Tuesday. The votes on so-called “Super Tuesday” take the presidential race to the national stage and is often seen as a sink-or-swim moment for candidates. “If Donald Trump becomes the Republican nominee, my expectation is that I will look for some third candidate—a conservative option, a Constitutionalist,” Senator Sasse said in an open letter on Facebook. “Mr. Trump’s relentless focus is on dividing Americans and on tearing down rather than building back up this glorious nation,” he said.