Sen. Arlen Specter (D-Pa.) signaled Tuesday he was not deterred by the Senate Finance Committee's votes to defeat two amendments in support of the public option.

Soon after learning that both proposals -- pitched earlier Tuesday afternoon by Sens. Jay Rockefeller (D-W.Va.) and Chuck Schumer (D-N.Y.) -- failed to win sufficient support from the committee's members, Specter tweeted:

I am disappointed by today’s vote in the Finance Committee preventing the inclusion of a public option in the health care reform bill.

One minute later, he added:

A robust public option will create competition in the marketplace and will help to provide affordable choices for American families.

Specter then concluded his string of tweets with a promise to champion his colleagues' cause once the Senate Finance Committee finishes its markup process:

I will continue to work with my colleagues for a public option once the legislation arrives at the Senate floor.

Despite Tuesday's setbacks, Specter and his fellow Democrats still have a number of avenues available to advance the public option.

Once the Senate Finance Committee finishes drafting its proposal, lawmakers will have to combine that with the Senate Health, Education, Labor and Pensions Committee's bill, which already boasts a government plan.

They will have another opportunity to append their proposal once the full Senate considers the committees' final health bill. And if the House approves a reform package with a public option intact -- which many lawmakers expect the chamber to do -- and the Senate approves any bill at all, a conference committee will provide proponents one last chance to defend their government plan.