This has not turned out to be a good week for the Republican Party-and that’s not even counting Newt Gingrich’s bumbling response to questions about a $500,000 line of credit he enjoys from Tiffany & Company (what on earth is that about?). The Republicans are now reeling from the loss of a special election for a congressional seat in western New York. It’s a loss with national implications that holds some important lessons for both sides.

More than anything, it is a stinging and embarrassing rebuke of the Republican Party’s preposterous plan to effectively kill Medicare, the national program that provides health coverage to seniors. It’s now clear that the victory of Kathy Hochul, the Democratic candidate for the seat, is a warning sign to Republicans everywhere that their party is hopelessly out of touch with working-class, middle-class America. Let’s face it: When your party loses in the most solidly crimson district of all of New York-a district that has sent Republicans to Congress for four decades-you’re in a heap of trouble.

The Republicans’ outrageous embrace of a proposal by Wisconsin Congressman Paul D. Ryan to turn Medicare into a voucher system is now striking a nerve, not just in New York, but across the nation. Blind support of this ill-conceived plan has become something of a litmus test for Republican presidential candidates, who have been derided by party leaders if they fail to take a blood oath to support the draconian measure.

But the contest in New York’s 26th Congressional District proved that there are some bedrock programs that voters don’t want to see trampled on-not even conservative Republican voters. Now the Republicans are scrambling to modify their view on the Ryan “Kill Medicare” bill. In the end, even the Republican candidate for the New York seat, Jane Corwin, tried to backpedal, saying that the Ryan bill she once championed was something “I’m not married to.”

Losing the seat is an astonishing blow to Republicans. The district, which sits between Rochester and Buffalo, is one of four of the state’s 62 districts that did not vote for Barack Obama in 2008. It has been represented by Republicans, including Jack Kemp, since the Nixon era. The Republicans spent more than $5 million to keep it in the Republican camp this time around. It didn’t work.

The loss has knocked Republicans for a loop. Even Congressman Peter T. King, the Republican from Long Island conceded to the New York Times, “We definitely have to determine the extent to which the Medicare issue hurt us.”

The lesson here is far more important for Democratic leaders than for their Republican counterparts. Let’s look closely: When it became clear that the Republican candidate endorsed the Ryan bill, Hochul, the Democratic candidate, immediately understood that defending Medicare was a bedrock issue that could not be compromised-she saw it as her ticket to winning the three-way race. She and her Democratic supporters were relentless and single-minded in linking her Republican opponent to the insanity of the proposal to end Medicare, a proposal that asks aging Americans to shop around for whatever bargains the marketplace might offer. She never let up.

And that’s the lesson that the Democrats-foremost among them President Obama-need to learn with clarity. There are certain bedrock programs and issues that should never be toyed with. Even the most passionate Obama supporters have been disappointed by the president’s mystifying penchant for compromise-especially back in the golden era of his presidency when the Democrats controlled both houses of Congress.

When it comes to Medicare, Social Security, health care and job creation, for example, the Democrats would do well to show more determination to keep their commitment sacred to working-class Americans. The president and congressional Democrats shouldn’t even imply that abandoning those programs and initiatives are matters up for discussion. In short, the results of the race in western New York should embolden the president and Democratic leaders to show, well, a little more backbone.