The more plausible argument is that Grassley fears his fellow Republican senators. I'm hearing that Grassley is getting reamed out in meetings with his colleagues. The yelling is loud enough that staffers in adjacent offices have heard snippets. But the real threat isn't the yelling of his colleagues. It's their capacity to deny Grassley his next job. Ruth Marcus hints at this in her column on Chuck Grassley today, but it's worth explaining in a bit more detail. This is the final year that Grassley is eligible to serve as ranking member — the most powerful minority member, and, if Republicans retake the Senate, the chairman — of the Senate Finance Committee. His hope is to move over as ranking member of the Judiciary Committee, or failing that, the Budget Committee. But for that, he needs the support of his fellow Republicans. And if he undercuts them on health-care reform, they will yank that support. It's much the same play they ran against Arlen Specter a couple of years back, threatening to deny him his chairmanship of — again — the Judiciary Committee. It worked then, and there's no reason to think it won't work now.