With the door slammed shut this week on federal legislation to create new protections for access to voting, Democrats face an electoral landscape in which they will need to spend heavily to register and mobilize voters if they are to overcome the hodgepodge of new voting restrictions enacted by Republicans across the country.

Democrats rode record turnout to win the presidency and control of the Senate in 2020 after embracing policies that made it easier to vote with absentee ballots during the pandemic. But Republican-controlled state legislatures have since enacted a range of measures that undo those policies, erect new barriers to voting and remove some of the guardrails that halted former President Donald J. Trump’s drive to overturn the election.

Now, Democrats’ best chance for counteracting the new state laws is gone after Senator Kyrsten Sinema, Democrat of Arizona, declared her opposition on Thursday to President Biden’s push to lift the filibuster to pass the party’s two voting access bills.

That failure infuriated Democrats and left them contemplating a long and arduous year of organizing for the midterm elections, where they already face headwinds from Mr. Biden’s low approval ratings, inflation, congressional redistricting and the persistent pandemic.

Democratic officials and activists now say they are resigned to having to spend and organize their way around the new voting restrictions — a prospect many view with hard-earned skepticism, citing the difficulty of educating masses of voters on how to comply with the new rules.

They say it would require them to compensate by spending tens or even hundreds of millions of dollars more on voter-registration and turnout programs — funds that might otherwise have gone to promoting Democratic candidates.

“All these voter protection measures are not cheap,” said Raymond Paultre, executive director of the Florida Alliance, a statewide network of progressive donors. “This is going to draw a lot of resources away from candidates, campaigns and organizations.”

Republicans, whose decades-long push to curtail voting access was put into overdrive by Mr. Trump’s false claims of election fraud following his defeat, are planning a renewed push to implement new restrictions during this year’s state legislative sessions.

They are also pushing to recruit thousands of Trump supporters as election workers come November.

The bottom line, Democrats say, is that in many Republican-run states, voting in 2022 may be more difficult — and more charged — than it has been in generations, especially if the coronavirus pandemic does not subside.

The stakes are highest in key battleground states where governors and top election officials on the ballot in November will determine the ease of voting in the 2024 presidential contest.

In Wisconsin on Thursday, a judge in Waukesha County, the largest county in the state among those run by Republicans, ruled that drop boxes for absentee ballots are illegal statewide — a reversal of longstanding practice, and a ban set to take effect in municipal primary elections on Feb. 15.

The ruling by Michael O. Bohren, a circuit court judge, invalidated years of guidance from the Wisconsin Elections Commission allowing municipalities to collect absentee ballots in drop boxes before Election Day.

Judge Bohren, who routinely attests to his bona fides as a conservative, was appointed to the bench in 2000 by former Gov. Tommy Thompson, a Republican, and presides over a courtroom displaying portraits of a handful of American presidents, all of them Republicans except for George Washington. He declined to be interviewed.

His decision, if not reversed on appeal, could also forbid Wisconsinites to turn in ballots other than their own and jeopardize city-sponsored ballot-collection events like Democracy in the Park in Madison, in which city workers gathered 17,000 early votes in public parks in the weeks before the 2020 election.

“When you try to suppress the vote, somebody is going to be at the losing end of things,” said Gov. Tony Evers of Wisconsin, a Democrat who faces a difficult re-election this fall. “Those people are the people of Wisconsin.”

The federal voting rights legislation also would have contained funding for election administration processes, including automatic voter registration. Without it, election officials say they will be hamstrung in training staff members and buying needed equipment, running the risk of disruptions. Hundreds of officials from 39 states sent a letter to Mr. Biden on Thursday asking for $5 billion to buy and fortify election infrastructure for the next decade. The letter was organized by a group largely funded by Mark Zuckerberg, Facebook’s founder and chief executive.

Despite that need, at least 12 states have passed laws preventing nongovernmental groups from financing election administration — a wide-reaching legislative response to false right-wing suspicions that $350 million donated for that purpose by another organization with ties to Mr. Zuckerberg was used to increase Democratic turnout. (The money mainly covered administrative expenses, including safety gear for poll workers, and was distributed to both Republican and Democratic jurisdictions.)

Some Democrats and civil rights leaders say they fear that the failure of Democrats in Washington to enact a federal voting law could depress turnout among Black voters — the same voters the party will spend the coming months working to organize.

“Voting rights is seen by Black voters as a proxy battle about Black issues,” said Mr. Paultre, in Florida. “The Democratic Party is going to be blamed.”

In Texas, whose March 1 primary will be the first of the midterms, some results of the sweeping new voting law passed by the Republican-controlled Legislature last year are already clear. In populous counties such as Harris, Bexar, Williamson and Travis, as many as half of absentee ballot applications have been rejected so far because voters did not comply with new requirements, such as providing a driver’s license number or a partial Social Security number.

In Harris County — the state’s largest, which includes Houston — roughly 16 percent of ballot applications have been rejected because of the new rules, a sevenfold increase over 2018, according to Isabel Longoria, a Democrat who is the county’s elections administrator. About one in 10 applications did not satisfy the new identification requirements, she said.

In Travis County, home to Austin, about half of applications received have been rejected because of the new rules, officials said. “We’re now seeing the real-life actual effect of the law, and, ladies and gentlemen, it is voter suppression,” said Dana DeBeauvoir, a Democrat who oversees elections there as county clerk.

Both counties have received far fewer absentee ballot applications than in 2018. Officials attributed the drop to a new rule barring election officials from sending ballot applications unrequested.

With the Texas primary fast approaching, election officials are growing increasingly worried about their ability to recruit poll workers. A variety of criminal penalties enacted in the state’s new voting law, they said, raise the risk that an honest mistake could land a low-paid worker in jail.

Republicans, whose most avid voters remain animated by Mr. Trump’s false stolen-election claims, have had no such trouble recruiting election workers. For Virginia’s November election, Republicans placed volunteers at 96 percent of precincts, up from 37 percent for the 2020 election, according to John Fredericks, a conservative talk-radio host who was Mr. Trump’s Virginia state chairman in 2020 and was a booster of the new Republican governor, Glenn Youngkin.

“That was the key to Youngkin’s victory,” Mr. Fredericks said.

Urging rank-and-file Republicans to work as poll watchers plays on their fears of voter fraud and helps reinforce party loyalty, G.O.P. officials say.

In Florida, Republicans will have their largest partisan election-observer operation ever, said Joe Gruters, chairman of the state Republican Party.

“There’s so many people that want to help and participate,” Mr. Gruters said. “It’s probably the easiest way to get people tapped in where they can have a meaningful impact, especially if they’re concerned about election-integrity issues.”

For Democrats, who are growing increasingly fearful of new criminal penalties established in new voting laws, a different kind of recruitment hunt is taking place — for lawyers.

The New Georgia Project, a progressive voting rights organization, has been working on training more than 1,000 lawyers on the new Georgia voting laws.

“Georgia already has some of the stiffer penalties for quote-unquote voter fraud in the country,” said Nsé Ufot, the group’s chief executive officer, “and then they went and added five new penalties.”

Georgia’s new voting law has already started to alter voting behavior. One central provision was a reduction in the number of drop boxes, felt most acutely in Atlanta’s Fulton County, where that number was slashed from 38 to fewer than 10.

In the municipal elections held last year, including a high-profile election for Atlanta mayor, drop box usage plummeted. The share of voters in the metro Atlanta region who used drop boxes plummeted by half compared with that in the 2020 election, according to The Atlanta Journal-Constitution.

Democrats have also expressed alarm about a provision of the new Georgia law that allows for the taking over of election administration in any county — even Fulton, home of the largest concentration of Democratic voters — by a state election board controlled by the Republican legislature.

Even as Republican legislators push voting curbs in statehouses, conservative legal organizations are suing to undo measures that eased access to the ballot in response to the coronavirus pandemic.

Wisconsin’s drop box case stems from an opinion in a December 2020 Wisconsin Supreme Court case in which Mr. Trump sought unsuccessfully to invalidate Wisconsin’s election results.

In a dissent, a conservative justice, Patience Roggensack, wrote that “drop boxes are not found anywhere” in state law, effectively inviting a legal challenge to them. “Challenges to drop boxes in general and in specific instances will be seen as problems in future elections,” she wrote.

Not long after, the Wisconsin Institute For Law & Liberty, a conservative think tank, sued to ban drop boxes — more than 500 of which were deployed for the 2020 election, many of them in Democratic-leaning cities.

After Thursday’s circuit court ruling, the case is likely to end up before the Wisconsin Supreme Court, giving Justice Roggensack a chance to rule on it.