Frustration with the botched, politically uncomfortable rollout of the president’s health care law is beginning to mount to unsustainable levels among congressional Democrats.

On Wednesday morning, Sen. Jeff Merkley (D-Ore.) announced that he was co-sponsoring a bill to allow individuals who buy their own insurance to stay on their current health care plans indefinitely rather than be forced into better regulated plans through the newly created exchanges.

Coming from one of the Senate’s most notably progressive voices, the Oregon Democrat’s announcement was a particularly vivid demonstration of how nervous party members are over the state of the Affordable Care Act. The flawed website, combined with the steady stream of news of insurers forcing people to adopt more comprehensive and at times expensive plans in response to new regulations, had already persuaded five other Democrats to support the Keeping the Affordable Care Act Promise Act, introduced by Sen. Mary Landrieu (D-La.).

Meanwhile, in the House, patience among Democrats was wearing remarkably thin. Lawmakers in that chamber were, by and large, staying away from a Republican-pushed measure that would allow people to stay on their plans for another year. But top aides were warning of a swarm of potential defections should the Obama administration not introduce its own administrative fix for the issue of canceled health insurance plans by the end of the week.

More: Obamacare Angst Among Democrats Approaches a Tipping Point