The liberals are as wrong now as the Republicans were then, except that their arguments and command of the facts are much shakier. The Senate's requirement for 60 votes to end debate is no historical accident, but rather a considered partial retention of the Senate's original precedent of unlimited debate. The House of Representatives abolished unlimited debate before the Civil War. The Senate kept it in place, instead checking its power by establishing a supermajority requirement to limit debate. Today, this requirement ensures consensus and frustrates self-styled revolutionaries who constantly seek major changes in policy.
When the Nation's Katrina vanden Huevel complains that "filibusters" killed such policies as the public option for Obamacare and a bigger economic stimulus package, she is really complaining that Senate rules are designed to resist left-wing radicalism by requiring reasonable consensus. The Founding Fathers, who properly viewed unrestrained majoritarian rule as the main undoing of democracies, would be happy to see her keep complaining. In Federalist No. 10, James Madison agreed with his contemporaries who worried "that our governments are too unstable ... and that measures are too often decided, not according to the rules of justice and the rights of the minor party, but by the superior force of an interested and overbearing majority." He also warned, in Federalist No. 62, against the very kind of constant changes to the law that a majoritarian system would essentially guarantee.
For all the liberals' complaints about the "undemocratic" filibuster, they should recall that there is a mechanism for overriding filibusters -- elect more senators who share your priorities. If the voters really held the public option in such high esteem as the liberals want to think, then surely they would have punished at least one of the sitting Republicans who resisted it by throwing him out of office last November. In fact, they did the opposite, proving that in some cases, the filibuster can actually protect a majority from misrule.