I think you are missing the point. Rush is looking at the “big picture”.
You keep her “alive” and with the delegates about evenly split. Then it becomes a brokered convention with the superdelegates the deciding factor. Even the numbnuts in the DNC know by now that Obama makes Hillary look like Miss America and that he is simply unelectable-more unelectable then Hillary. So they will have the superdelegates vote for Hillary which will give her the nomination. If that happens you will see the radical left wing go into full meltdown mode. It will split the party and quite possibly cause so much rancor at the convention that even the MSM can’t cover it up or spin it which will show the true face of the Democratic party to America.
The radical left wing of the party (always known for their common sense and political savvy) will do a couple of things. The more radical of them will vote and work for for Nader or McKinney but all of them will take their anger out on Hillary. Depending on how it plays out that could cost anywhere from 3% to 10% of votes that would have voted for a Democrat to go elsewhere. And in states such as Washington, California, Minnesota, Louisiana, Wisconsin etc. to possibly go from solid, dependable blue to a toss up or red. That means the party has to spend more time and effort on those states to keep them then they would like to. And every dollar/minute they have to spend on keeping their existing territory is one less dollar/minute then can spend in places like Colorado, Oregon, Ohio, etc.
What are you basing that assertion on? The fact that his supporters show no enthusiasm? The fact that the press hates him? The fact that his base isn't in tact? The fact that the country is sick of him after 8 years of his spouse in the Whitehouse? The fact that he's a nasty old hag that looks worse every day? The fact that he can't captivate air-headed young voters with meaningless platitudes?