That's the other problem. If you don't vote down party lines, you're called out on it, won't get support for your own bills, and the party leaders call you poopy head and leave nasty voice mails on your phones.
*Those last two points might be hear-say.
Both parties have dug in their trenches and have loaded their poo catapults. There is little compromise anymore. It's all about the instant approval ratings and this week's face time on the news.