WASHINGTON — When President Biden spoke Tuesday from a lectern at the end of the White House Cross Hall to mark the end of the 20-year U.S. war in Afghanistan, he declared the 11th-hour airlift to be “an extraordinary success,” despite having left at least a few hundred Americans behind. He rebutted head-on various criticisms of the chaotic withdrawal and was firm in his resolve to end a war that he — and a majority of the country — believed was no longer in the national interest.

But he didn’t just read the remarks off the teleprompter. He seemed to shout them. The president’s anger and frustration were palpable, as was his innate stubbornness.

The grandfatherly Biden has modeled his presidency on Franklin D. Roosevelt’s. But this was no fireside chat. And yet, his emotion seemed to reflect that of the country: deeply polarized, self-certain, constantly outraged. His remarks underscored the difficulty of revitalizing the political center in a moment when the center, it seems, cannot hold.

Aides, questioned publicly about the president’s tone, said it reflected his deep “convictions.” But privately, several acknowledged that Biden is frustrated about the barrage of criticism in recent weeks — especially from those who bear responsibility for miscalculations that escalated and extended the war and from news media that, after ignoring the conflict for years, took up the cause of the Afghan people with avidity and lay the blame for a defeat that was years in the making at the president’s feet.

And there is no doubt about the political toll Biden is paying for ending a conflict that three other presidents allowed to drag on.

While polls this week showed that a majority of Americans agree with Biden’s decision to end the war, they give him lower marks for his execution of the pullout. Biden’s overall approval rating has fallen in the last month from a net positive of 8.1 percentage points to a net negative of 0.4 points, according to the FiveThirtyEight polling average. Pollsters attribute the slide to not just Afghanistan but also the resurgence of the COVID-19 pandemic.

Few members of Washington’s political class expect Afghanistan to remain a top issue for voters in the November 2022 midterm election, but the issue has finally given Republicans an effective point of attack on a president who had been mostly impervious to their broadsides.

Even with the midterm more than a year away, the timing of Biden’s eroding support could be costly for his domestic agenda. It faces a make-or-break month in Congress, as does his party, with Republicans looking to knock out Democratic governors in California and Virginia this fall.

This is an administration, populated by aides with past West Wing experience, that believes deeply in its managerial abilities and has absorbed the lessons from past mistakes. Determined to keep Biden’s ambitious domestic agenda on track, aides set up a “war room” in late July to coordinate a public outreach effort to build support for the bipartisan infrastructure bill, which the Senate passed last month, and a Democratic budget bill teeming with benefits for workers and families.

The chaotic Afghanistan pullout, which upended Biden’s vacation plans and left his daily schedule in flux, threw the West Wing into crisis mode for the first time during his presidency. It punctured somewhat the aura of competence the administration had spent eight months establishing and stands to complicate efforts to keep its ambitions and tactically complex legislative push on track.

The storm of events only complicates the administration’s messaging efforts, leaving Biden’s agenda overshadowed by Afghanistan, the pandemic and other calamities, including wildfires in the western U.S. and devastating hurricanes — all as the president has been forced to stand idly by amid the GOP’s assault on voting and reproductive rights at the state level (more on this later). And Friday’s dismal jobs numbers, a clear sign that the Delta surge is strangling the economic recovery, didn’t help.

Even if Biden and Democrats succeed in passing their domestic agenda, resulting in new projects to upgrade roads, bridges and rail lines, as well as new subsidies for parents and students, there is no guarantee it will be enough for the party to run on next year. After passing a $1.9-trillion coronavirus relief measure in March, Biden urged fellow Democrats to take credit and make sure the country knew which party was responsible for the $1,400 direct relief checks that went to 80% of Americans.

A survey conducted last week by Civiqs, a Democratic polling firm, asked respondents if they believed the Biden administration has “done anything that has benefitted you personally.” Only 37% said yes, while 57% said no. That’s the clearest sign yet of the political challenge Democrats face: They not only have to enact their agenda; but they also have to figure out how to turn it into a winner.

In recent weeks, Biden has strayed from his initial strategy of lowering, then exceeding, expectations. It’s a shift that helps explain the dip in his support.

Upon taking office and focusing above all on getting the pandemic under control, Biden made a point of setting modest goals that were easily achieved. For instance, he promised 100 million shots of vaccine in his first 100 days and met that goal on Day 58. And he initially suggested that it would be July before there were enough vaccine doses for every adult American, only to announce in early March that the country would have enough by May.

But as the tide started to turn, Biden succumbed to the temptation of hyping good news. On the Fourth of July, he hosted a large gathering on the South Lawn of the White House and declared America’s “independence” from the virus. It wasn’t long, of course, before the contagious Delta variant started to spread.

Similarly, Biden repeatedly downplayed the potential for a swift Taliban takeover of Afghanistan. In July, even as the Taliban was starting to overtake the country’s military, Biden insisted that the situation was “not at all comparable” to America’s harried 1975 departure from Saigon.

“There’s going to be no circumstance where you see people being lifted off the roof of a[n] embassy in the — of the United States from Afghanistan,” he promised roughly a month before that very scenario took place.

Given that Afghanistan and the resurgent pandemic are both responsible for the sudden dip in his poll numbers, it’s easy to see how the president’s comments raised the public’s expectations and set him up to pay a political price when he failed to meet them.

Animated by attacks on “cancel culture,” intraparty loyalty tests and, in last week’s episode, attempting to intimidate telecommunications companies to thwart the congressional investigation of the Jan. 6 insurrection, Republicans have generally shied from telling voters what they would do if they take back Congress next year.

Democrats say the priorities are easy to divine — if you check out Republicans’ record in state legislatures.

Already this year, 18 states have enacted laws that make it harder for people to vote by limiting or complicating mail-in and early voting and imposing stricter voter ID requirements.

And the Supreme Court early Thursday refused to strike down a Texas law that bans abortions after six weeks of pregnancy and incentivizes individuals to sue anyone suspected of flouting the law, setting up what one provider called “a bounty system.” Clinics saw a spike in the number of women seeking abortions just before the law went into effect.

The very real erosion of women’s constitutional rights to abortion, as affirmed in Roe vs. Wade, has immediately thrust another emotional, galvanizing issue to the forefront. As with voting rights, it’s not an issue against which the Biden White House or Democrats can muster much of a counterattack.

The administration prioritized pandemic relief and infrastructure because it viewed them as urgent and necessary, not to mention potentially unifying and achievable. But with Biden at a point where he needs Democrats to line up behind his infrastructure and jobs bills, his party’s base is understandably outraged — and focused on — other issues, demanding more than rhetoric in response to what they see as a partisan assault on established and fundamental rights.

Perhaps the GOP assault on Roe will galvanize female voters. But if Biden and Democrats can’t muster a policy response beyond encouraging their voters to show up next year, some of those voters may become so frustrated they decide to stay home.