One image perfectly captured the absurd, irrational and wholly unnecessary confrontation over whether to shut down the federal government on the basis of differences over a small part of the budget.

During a Tea Party rally near the Capitol last Wednesday — “rally” being generous for a gathering of a few hundred people — Rep. Mike Pence, the Republican fire-eater from Indiana, declared that if Senate Democrats refused to accept “a modest down payment on fiscal discipline and reform, I say, ‘Shut it down!’ ”

And the crowd erupted, lustily and joyfully: “Shut it down! Shut it down!”

As the shouting persisted, it became clear that the government of the most powerful country in the world was being held hostage by a band of fanatics who (1) represent a very small proportion of our population; (2) hate government so much that they relished the idea of closing its doors, no matter the cost; and (3) have neither respect nor patience for the normal democratic give-and-take between competing parties and points of view.

In no serious country do threats to shut down the government become a routine way of doing business. Yet in our repertoire of dysfunction, we are on the verge of adding shutdown abuse to abuse of the filibuster in the Senate.

Republicans, however, were rewarded for going to the brink. Because so many on House Speaker John Boehner’s side were eager for a shutdown and President Obama was so determined to avoid one — and to stay out of the spotlight until the final days — Boehner had the upper hand.

Republicans have won two rounds since December: on tax cuts for the wealthy and now on spending cuts. At least Obama got some economic stimulus out of last year’s tax deal. The latest agreement is a modest setback to economic growth and, depending on how you want to count, gives Republicans either three-fifths or close to four-fifths of the cuts they sought.

True, the administration and Senate leader Harry Reid pushed Boehner toward more sensible cuts, protected important programs such as Head Start, and beat back the GOP’s proposed policy changes on family planning, the environment and other issues. But notice that these victories were largely defensive. Republicans, with control of just one house of Congress, defined the terms of debate. “Concessions we can believe in” was not the slogan Obama ran on.

At the heart of Obama’s “Win the Future” State of the Union address was an argument that government action is essential in making the United States more competitive and innovative, and in expanding opportunity for Americans who are being left behind. By distancing himself from this round of the budget debate, the president forfeited an opening to challenge the anti-government assumptions embedded in Republican arguments that are shaped far more by the Tea Party than the movement’s numbers in the country (or its falling poll ratings) would justify.

Of both big policy battles since the 2010 elections, Obama insisted that the most important thing was to get them behind us so we could move on to the main act. But when, exactly, will the main act begin? When will he fully engage? When will he challenge the idea that government’s central obligation is to shrink itself?

The vast majority of Americans oppose shutdowns. They do not share the aggressive antagonism toward government that is distorting our politics. Unless Obama gives voice to this sensible sentiment, we will face more episodes like this one. For if government is turned into something evil, no one has an obligation to stewardship of its institutions. Recklessness in pursuit of political victory becomes a virtue. Indifference to those who are served by or work in government becomes a badge of honor.

In those Tea Party shouts of “Shut it down,” the “it” drips with contempt. We cheer when drug dens or terrorist havens are shut down. There should be no glee over shutting down our government. Threatening the functioning of the public sphere is not an acceptable tactic in a democracy.

For Obama, it is not good enough to cast himself as the school principal scolding competing congressional gangs. He needs the courage to defend the government he leads. He needs to declare that he will no longer bargain with those who use threats to shut down the government or force it to default on its debt as tools of intimidation. We’re all a bit weary of Obama telling everyone to be grown-ups, but this would be the grown-up thing to do.

ejdionne@washpost.com