For Republicans, the vast majority of that money has gone to protecting incumbents.

A desire to protect incumbents in both major parties drove the plan.

Senate Republicans have long shifted money between campaign accounts to protect incumbents.

Some Democrats worried that they had done too much to protect incumbents.

First, the parties try to protect incumbents, by eliminating from a district those pockets where support is weak.

But over the years the laws have come to protect incumbents against challenges from insurgent candidates.

Some who study campaign finance worry that spending limits would protect incumbents.

"There are those who suggest that members drawing their own lines every 10 years is done primarily for the purpose of protecting incumbents."

District lines have been painstakingly drawn to protect incumbents, and to help the party with control over the process.

The party's leaders in Sacramento decided to concentrate on protecting incumbents.