Back in 1792, Thomas Jefferson was fed up. The Federalists, led by (tastefully named) Alexander Hamilton, were trying to pass legislation to establish a national bank, to shore up the Federal governments primacy over the states, and to establish a treaty with Britain (who was at war with France). Jefferson retaliated by forming the "Democratic-Republican" party. For simplicity they were called "the republicans". From 1800-1824 this party held the majority in both the House and Senate, and eventually became so large that party unity dissolved and the party split into the Jefferson loyalists: "the democrats" and several other groups. None of those groups was the modern Republican party as we know it today; that party formed in 1854 as an anti-slavery party.
Anyway, the point is, in 1820 James Monroe ran under the party's banner for President and was elected almost unanimously in the electoral college. Four years later the party fractured.
Is this the future of the Democratic Party? With Specter now entrenched in the Democratic party, but still claiming to be at least moderate, and with the possibility that the Dems might gain more Senate and House seats in the 2010 election, I have to wonder if the Democratic party is on its way to utter dominance...and then utter collapse.
Could the Democratic party soon get so big and broad-ranged in political attitudes that it fractures? Ask the Blue Dogs.