http://www.c-span.org/questions/weekly55.htm<snip> The Blue Dogs derive their name from the artwork of a Cajun painter, George Rodrigue, well known in Louisiana for his series of paintings featuring an unusual blue dog. The fledgling members of what became the Blue Dog Coalition used to meet regularly in the offices of then-Democrats Rep. Billy Tauzin and Rep. Jimmy Hayes of Louisiana. Tauzin has since switched to the Republican party and Hayes was defeated in a run for the Senate. The Louisiana representatives had Rodrigue’s blue dog paintings displayed on the walls of their offices, and these provided the inspiration for the coalition’s name. One of the Blue Dogs, Rep. John Tanner from Tennessee, maintains that Blue Dogs are simply “yellow dogs that have been choked by extremes in both political parties to the point they have turned blue.”
<snip> Blue Dog Democrats are an actual voting coalition made up of Members of Congress, whereas Yellow Dog Democrat is an expression -- it describes a certain kind of voter. Nor are Blue Dogs ideological relatives of the "Yellow Dogs" of the South, even though they have similar names.
<snip> When the South as a region was a political stronghold for Democrats in the first half of the 20th century, it was said that a Southern voter would vote for a mangy yellow dog before he/she would vote for a Republican. So a “Yellow Dog Democrat” implies one fiercely loyal to the Democratic party, with a strong partisan profile. The expression achieved prominence in the 1928 presidential campaign when southern Democrats, reluctant to support their national party's nominee, Al Smith, voted for him anyway, out of loyalty to the party ticket. When the term is used today, it is meant as a compliment to one who remains a true Democrat, no matter what.
<snip> The Blue Dogs, on the other hand, are less fiercely partisan, and they do not all hail from the South. They seek to build ideological bridges to the Republican side of the aisle, are known for their independence from the leadership of their own party, and tend to be more pragmatic than partisan. Blue Dogs are closer in purpose to a former coalition of southern Members of the House known as the “Boll Weevils,” whose heyday was in the early 1980's. These Members defected as a group from the Democratic party to vote with Congressional Republicans on budgetary and tax bills. However, all Southerners, they were named after the insect that infected and often destroyed cotton crops, so the name “Boll Weevil” had a pejorative implication.