Well said by the terrific Dick Polman:

And yet...the Democrats really have no alternative but to enact something. They're too far in to back out.

If they now abandon health reform, after seven fitful decades, they will lose politically at both ends of the spectrum. Since they're already on record, in both chambers, as having voted Yes on health reform, a retreat at this point would give the Republicans a two-fer message: "Democrats engineered a socialist takeover of the health care system - until they flip-flopped! They were for a takeover until they were against it!" And the Democratic base would simply stay home on the '10 election day for its own reasons - having become convinced that it doesn't pay to elect large Democratic majorities, since those majorities clearly lack the cajones to get anything done.

The only viable alternative for Democrats is to persevere and stick to their policy convictions (thus keeping faith with their base), and remind themselves that Ronald Reagan and George W. Bush stuck to theirs even when public opinion was against them (Bush, especially, persevered on his ambitious Medicare drug prescription bill in December 2003 even though only 32 percent of the general public, and only 26 percent of seniors, supported it). It would better for Democrats to have something affirmative to show for their efforts, to campaign this year as the party that (in the face of Republican opposition) barred insurance companies from dropping sick people, that barred insurance companies from denying coverage to people with pre-existing conditions, and that extended health coverage to millions who lacked it before. This political option might not work either, but it's surely more attractive than the fetal position.