The 27th president of the United States - William Howard Taft.
The only man to have served as president, and chief justice of the United States. Apparently he preferred the latter.
It seems crazy to me to label either Taft or Roosevelt as republicans. Their more progressive politics don't even have a passing resemblance to the current GOP. If you look at the electoral maps between 1908 and 2008 they are almost completely reversed.