1916: Roosevelt Runs

[gorkay]

Hughes being a "progresssive" is news to me. He made some feints that way in the campaign to woo voters who went Bull Moose in 1912, but he was pretty conservative deep-down. That's why the Progressive party convention went into revolt in 1916 when TR suggested they nominate Hughes.
TR didn't much like Hughes, either... he called him "Wilson with whiskers." But by 1916, TR had realized that he would never get back to the White House as a third-party candidate and was laying the groundwork to run for the Republican nomination in 1920. So he endorsed Hughes, but I doubt that he was unhappy when he lost.
Another factor was that, in 1916, Roosevelt was suffering a temporary downswing in personal popularity because he was much more hawkish on the war than the American public. The Wilson campaign even used his hawkishness against Hughes in the campaign... "Wilson and peace with honor, or Hughes with Roosevelt and war?" was one of their slogans.
The upshot: if TR had run, he wouldn't have done nearly as well as in 1912, and would have increased Wilson's margin of victory in both the PV and EV.