Several of the 'minor party' candidates fit the scenario, Eugene V. Debs ran as a Socialist in 1904,'08,'12 and 1920. But as for the 'major parties' its happened twice in my life time. The most recent time is 1960. Richard Nixon(Rep)ran against and lost to John Kennedy. Nixon ran again 1968 and won against Hubert Humphrey . Adlai Stevenson(Dem) ran against and lost to Dwight Eisenhower in 1952 and 1954. William Jennings Bryan ran against and lost to William McKinley, first in 1896 as a 'Democrat/Populist,' then in 1900 as a Democrat, and then again in 1908 against William Taftas a Democrat. Now (or then, since I'm goin backwards, and then forwards) we got Grover Cleveland (Dem) he beat Blaine( the continental liar from the state of Maine) in 1884, then lost to Benjamin Harrison in '88, then won against Harrison in 1892. Things get confusing in 1860, the Democrats splinter into at least three parties, Democrats, Free Soil Democrats, and Constitutional Union Democrats. Prior to that its really confusing, there were a bunch of splinter groups, single interest parties, even down right biggotted secret societies, old parties dying, new parties forming to basically become what we now call Republicans and Democrats. There were people who had been their parties nominee but when not renominated ran under another party label. Millard Fillmore (Whig) had even been the Prez. 1850-53 but did not get the party nomination. He ran in '53 for the American Party ( the No Nothings.) William Harrison (Whig) lost to Martin Van Buren (Dem) in 1836, but then beat Van Buren in 1840, then Van Buren lost to Zachery Taylor (Whig) in 1848 as a Free Soiler. Now comes the biggest change in politics since 1860, which hasn't happened yet in this two steps back, one forward timeline of mine.( Made more confusing since I time jumped back and killed the Bag's direct ancestor, so you can't be reading this now, the year 203 of the Emperium.) 1824 Andrew Jackson(Democratic-Republican) loses to John Q. Adams(Dem-Rep), then 1828 Jackson (Dem) beats Adams(National Republican.) 1812, Rufus King (Federalist) loses to James Madison(Dem-Rep) Then again in 1816 to James Monroe, who had lost to Madison in 1808 ( both Dem-Rep.) 1804 Thos. Jefferson (D-R) beats Charles Pinckney( Fed), he beat Pinckney in 1800 too. but 1804 was the 1st partisan election. Before that 1st place was Prez, 2nd place VP. Yeah, like that'll work. Bush as Prez, Gore VP. Confused? I am. Now let me 'splain the electoral college, tho I did skip a lot of classes. I only enrolled to escape the draft for the Droid Wars. And from all the clues you should be able to come within a year or two of guessing my age. Get it right, and under the rules of the Imperium, you win two non-consective nominations to run for Major of the Party.