This time is different. What is at stake in this government shutdown forced by a radical Tea Party minority is nothing less than the principle upon which our democracy is based: majority rule. President Obama must not give in to this hostage taking — not just because Obamacare is at stake, but because the future of how we govern ourselves is at stake.

What we’re seeing here is how three structural changes that have been building in American politics have now, together, reached a tipping point — creating a world in which a small minority in Congress can not only hold up their own party but the whole government. And this is the really scary part: The lawmakers doing this can do so with high confidence that they personally will not be politically punished, and may, in fact, be rewarded. When extremists feel that insulated from playing by the traditional rules of our system, if we do not defend those rules — namely majority rule and the fact that if you don’t like a policy passed by Congress, signed by the president and affirmed by the Supreme Court then you have to go out and win an election to overturn it; you can’t just put a fiscal gun to the country’s head — then our democracy is imperiled.

This danger was neatly captured by Washington Post columnist Dana Milbank, when he wrote on Tuesday about the 11th-hour debate in Congress to avert the shutdown. Noting a shameful statement by Speaker John Boehner, Milbank wrote: “Democrats howled about ‘extortion’ and ‘hostage taking,’ which Boehner seemed to confirm when he came to the floor and offered: ‘All the Senate has to do is say ‘yes,’ and the government is funded tomorrow.’ It was the legislative equivalent of saying, ‘Give me the money and nobody gets hurt.’ ”“Give me the money and nobody gets hurt.” How did we get here? First, by taking gerrymandering to a new level. The political analyst Charlie Cook, writing in The National Journal on March 16, noted that the 2010 election gave Republican state legislatures around the country unprecedented power to redraw political boundaries, which they used to create even more “safe, lily-white” Republican strongholds that are, in effect, an “alternative universe” to the country’s diverse reality.

“Between 2000 and 2010, the non-Hispanic white share of the population fell from 69 percent to 64 percent,” wrote Cook. “But after the post-census redistricting and the 2012 elections, the non-Hispanic white share of the average Republican House district jumped from 73 percent to 75 percent, and the average Democratic House district declined from 52 percent white to 51 percent white. In other words, while the country continues to grow more racially diverse, the average Republican district continues to get even whiter.”According to Cook, the number of strongly Democratic districts decreased from 144 before redistricting to 136 afterward. The number of strongly Republican districts increased from 175 to 183. “When one party starts out with 47 more very strong districts than the other,” said Cook, “the numbers suggest that the fix is in for any election featuring a fairly neutral environment. Republicans would need to mess up pretty badly to lose their House majority in the near future.” In other words, there is little risk of political punishment for the Tea Party members now holding the country hostage.

Meanwhile, the Supreme Court’s inane Citizens United decision allowed a single donor, Sheldon Adelson, to create his own alternative universe. He was able to contribute so much money to support Newt Gingrich’s candidacy that Gingrich was able to stay in the Republican presidential primary race longer than he would have under sane campaign finance rules. As a result, Gingrich was able to pull the G.O.P.’s leading candidate, Mitt Romney, farther to the right longer, making it harder for him to garner centrist votes. Last month, for the first time ever in Colorado, two state senators who voted for universal background checks on gun purchases lost their seats in a recall election engineered by gun extremists and reportedly financed with some $400,000 from the National Rifle Association. You’re elected, you vote your conscience on a narrow issue, but now determined opponents don’t have to wait for the next election. With enough money, they can get rid of you in weeks.

Finally, the rise of a separate G.O.P. (and a liberal) media universe — from talk-radio hosts, to Web sites to Fox News — has created another gravity-free zone, where there is no punishment for extreme behavior, but there’s 1,000 lashes on Twitter if you deviate from the hard-line and great coverage to those who are most extreme. When politicians only operate inside these bubbles, they lose the habit of persuasion and opt only for coercion. After all, they must be right. Rush Limbaugh told them so.

These “legal” structural changes in money, media and redistricting are not going away. They are superempowering small political movements to act in extreme ways without consequences and thereby stymie majority rule. If democracy means anything, it means that, if you are outvoted, you accept the results and prepare for the next election. Republicans are refusing to do that. It shows contempt for the democratic process.

President Obama is not defending health care. He’s defending the health of our democracy. Every American who cherishes that should stand with him.