The left is lashing out at a proposal to reform Medicare that President Obama said he would consider as a way to reduce the deficit.

Left-leaning groups and liberal lawmakers say that combining Medicare’s doctor and hospital coverage would saddle beneficiaries with higher costs. The idea has attracted support from leading Republicans, and given Obama’s receptiveness, the policy could receive significant attention in the next round of deficit-reduction talks.

This is exactly what senior advocates fear, and they are launching pre-emptive strikes on Capitol Hill to ensure lawmakers understand the downside.