Megan McArdle warns that trying an end run around the Senate’s rules will prove a costly mistake for democrats.

If the Democrats use budget reconciliation to bypass the Republicans, they will be making a big mistake.

Reconciliation is not meant to handle these sorts of problems; it’s meant to help Congress get revenues in line with outlays without letting protracted negotiations push us into a budget crisis. It’s not possible to do any sort of comprehensive, rational overhaul of the Senate health bill — which after all, was intended to be the opening salvo in a negotiation, not the final bill.

More broadly, for all that Democrats are declaring that they have a mandate, it’s pretty clear that the public does not want them to pass any of the health care bills on the table — which has to include the Obama plan, since it is only a minor tweak on the existing proposals. Polls have shown more Americans opposing passage than supporting it since early summer, and opposition has risen fairly steadily over time.

Democrats have had plenty of time to make their case. They have failed to do so. The longer they have talked, the more firmly the voters have rejected their ideas. If Congress goes ahead anyway, they will pay a terrible political price.

Many progressives are pushing the notion that having already once voted for it, Democrats will pay that political price no matter what, so they might as well pass it. That ignores several factors. First, a hated bill that failed last December is not going to engender the same ire as a hated bill that passed in May.