They might not realize it yet, but President Obama’s liberal supporters have had a rough week.

On Monday, they watched and cheered as their triumphant leader outlined a boldly progressive vision for the country, hitting all the high points: climate change, gay rights, equal pay, immigration reform, entitlement denialism, and “peace in our time.”

But whatever hopes they may have had for realizing that vision suffered a serious blow yesterday. It happened the moment Senate Majority Leader Harry Reid (D., Nev.) scrapped his plans to “nuke” the filibuster. Eliminating the filibuster would have effectively stripped the minority party (today, the GOP) of its longstanding ability to block or stall major legislation.

It would have been a power play of bold and unprecedented proportions. Had Reid followed through, his Democratic majority could have swiftly approved a laundry list of long-coveted liberal policies and brought considerable political pressure to bear on the Republican-controlled House of Representatives. Such extraordinary action would also have been in keeping with the spirit of Obama’s inaugural address. “Progress . . . require[s] us to act in our time,” he said. “We cannot afford delay.”

But it was not to be. The Senate on Thursday approved a package of minor rule changes — keeping the filibuster, and the 60-vote threshold to end it, essentially intact. The passage of any major legislation in the next two years will require support from at least five Republicans.

The filibuster’s survival likely guarantees at least two more years of bitter stalemate between the Democrat-led Senate and the GOP-controlled House. At best, Obama may be able to enact part of his agenda through executive order, peel off a few Republicans on issues like immigration reform, and hope Democrats retake the House in 2014, a fairly unlikely scenario.

Those who were paying close attention — liberal activists, many of whom had seen their pet causes (card check, cap-and-trade, a health-care public option) defeated by filibusters during the president’s first term — were appropriately demoralized.

“This is a bad decision based on fear — a decision that will ultimately hurt millions of people who would have been helped by progressive bills that Republicans are sure to filibuster,” said Adam Green, co-founder of the Progressive Change Campaign Committee, which had lobbied Senate Democrats to deploy the so-called nuclear option and effectively eliminate filibusters.

Fix the Senate Now — a coalition of left-wing groups, including the Sierra Club and several labor unions, that claimed to have made 100,000 phone calls, gathered 1 million petition signatures, and sent more than 2.5 million e-mails to lawmakers in support of so-called filibuster reform — called it a “missed opportunity.”

Bob Edgar, president of coalition member Common Cause, went further, denouncing Reid’s “capitulation.” “This is not the Senate of debate and deliberation our founders envisioned,” he said, perhaps mimicking Obama’s repeated invocation of the nation’s founding as a blueprint for progressive reform.

Mother Jones recently reported on a secret meeting of more than 30 prominent liberal interest groups (the National Education Association, Greenpeace, and the NAACP, among others) that took place a month after the president’s reelection. The “most pressing issue” at the meeting? Filibuster reform.

MSNBC host and left-wing outrage bellwether Ed Schultz delivered a seemingly astute rant via his Facebook page, albeit in slightly exaggerated terms. “I can’t believe what Harry Reid did today,” Schultz said. “He just handed [Senate Minority Leader] Mitch McConnell all the ammunition to destroy the Obama agenda. So much for immigration reform. So much for a jobs bill. So much for anything!”

The liberal outrage was justified, according to a Senate Republican aide. “Gutting the filibuster was the top priority and the first test of muscle for the vaunted liberal juggernaut heading into Obama’s second term,” the aide says. “The fact that it completely fizzled not only explains the hysteria we’re seeing on the left, it should boost the spirits of conservatives looking for signs of hope after Obama’s inaugural.”

Ultimately, it was Democrats who talked Harry Reid out of going nuclear, even though he likely would have had the votes to do it. Many of his colleagues, and probably Reid himself, were too respecting of the Senate as an institution to permit such a sweeping rule change, especially under such hostile conditions.

That was a tough pill for liberal reform advocates to swallow. Some may well have suffered flashbacks to 2009–10, when wavering Democratic senators helped scuttle cap-and-trade, card check, and the public option. During much of that time, Democrats enjoyed a filibuster-proof majority.

Not only that, but Harry Reid had for months been promising big changes to the Senate rules, only to settle for a watered-down compromise. Expectations were understandably high, and no doubt reinforced by Obama’s hard-hitting inaugural address, in which he promised to take the fight to Republicans.

The president, for his part, praised the Senate compromise. “At a time when we face critical decisions on a whole range of issues — from preventing further gun violence, to reforming our broken immigration system, to getting our fiscal house in order and creating good paying jobs — we cannot afford unnecessary obstruction,” Obama said in a statement Thursday. “I am hopeful that today’s bipartisan agreement will pave the way for the Senate to take meaningful action in the days and weeks ahead.”

If that is what he really believes, he is bound to be as disappointed as his liberal allies are already.

— Andrew Stiles is a political reporter for National Review.