I'm starting another "US with another country's party system" series. This time with the UK. The results won't be as worked out as the "US as Canada" series (at least initially), but by 2012 a methodology should definitely appear.
Also, expect quite a bit of OTL UK results to be mirrored in the series.
The Red, Green, and Blue
Following the 1924 election, a political earthquake occurred. Members of the increasingly liberal Democrats, incensed at having the conservative John W. Davis for their nominee and disgruntled by southern domination of the party, began switching to the Progressive Party in droves. The party, which otherwise might have suffered the fate of so many third parties in American history, found itself invigorated to an extent never before seen and in 1926 the shocked establishment watched as the Progressives became the dominant opposition party outside of the south.
President Coolidge was briefly tempted to run again in 1928, but in the end decided not to and Commerce Secretary Herbert Hoover won the GOP nomination. The Progressive chose Burton K. Wheeler, a senator from Montana as their standard-bearer, while the Democrats, still shocked at the rapid change in the party that had occurred since 1924, nominated their top candidate: New York Governor Al Smith.
Smith's Catholicism turned off a lot of Americans, who still harbored anti-Catholic prejudice. The contest, which had formerly been seen as a GOP cakewalk, turned into a fierce competition between Hoover and Wheeler. In the end, vote-splitting between the Democrats and Progressives enabled Hoover a comfortable electoral college victory, while Smith forebodingly won only states in the Deep South.