It’s also worth being clear on this: The Republicans do this the right way. The Senate Republican caucus is organized, like the House caucuses of both parties, like a partisan political organization whose objective is to advance the shared policy objectives of the party. The Senate Democratic caucus, by contrast, is organized like a fun country club trying to recruit members. Join Team Democrat and Vote However You Want Without Consequence! But it’s no way to get things done.I wouldn't dispute that in broad strokes the Republicans have run a tighter ship than the Democrats, particularly in the Senate. But, the ship has also spring a lot of leaks. Consider the fate of the 10 most liberal Republican senators as of the start of George W. Bush's first term:
1. Lincoln Chafee (RI) - lost to Sheldon Whitehouse in 2006
2. Jim Jefforts (VT) -- began to caucus with Democrats on 6/6/2001. Retired in 2008.
3. Arlen Specter (PA) -- switched affiliation to Democratic Party on 4/29/2009.
4. Olympia Snowe (ME) -- voted with Democrats on stimulus; likely to do so on health care and climate bill. Won re-election in 2004.
5. Susan Collins (ME) -- voted with Democrats on stimulus; probably will not do so on health care. Won re-election in 2002 and 2008.
6. John McCain (AZ) -- has since become more conservative. Lost Presidential election in 2008.
7. Gordon Smith (OR) -- lost to Jeff Merkley in 2008.
8. Peter Fitzgerald (IL) -- retired in 2004; seat won by Barack Obama.
9. John Warner (VA) -- retired in 2008; seat won by Mark Warner.
10. Thad Cochran (MS) -- has generally been a loyal Republican vote. Won re-election in 2002 and 2008.
So, to summarize, that's two defections (Jeffords and Specter), two losses (Chafee and Smith), two retirements (Warner and Fitzgerald), two Senators that the party can pretty much no longer rely upon (Snowe and Collins), and finally, two who have indeed become more conservative and remained loyal to their party (McCain and Cochran). That's a .200 batting average, which isn't good in baseball and isn't any better in the Senate.
Again, I don't necessarily mean to suggest that the Republicans have done anything strategically wrong. They had a pretty good run during the first 5 1/2 years or so of George W. Bush's term, steering the country in a substantially conservative direction.
But to suggest that party discipline is a mere matter of cracking the whip a little harder is an incomplete explanation. Certainly, there is an art to vote-whipping -- one which, for instance, Nancy Pelosi understands a lot better than Harry Reid. But also, a lot of it is a question of what long-term price you're willing to pay for short-term gains. And a lot of it is also circumstantial: the smaller your conference and the less ideologically diverse, the easier that loyalty tends to be. If the only two Republican senators were Tom Coburn and Jim DeMint, well then, by golly, they'd be really, really, really disciplined. They'd also be completely powerless to stop the 98 Democrats.