Democratic state officials are ramping up their preparations to protect against what they view as a new threat to election security: the federal government.

At a meeting in Milwaukee in May, staff members from the offices of every Democratic attorney general and about a dozen Democratic secretaries of state held tabletop exercises to prepare for hypothetical scenarios in the November midterm elections.

In those “war rooms,” said Nick Brown, the Democratic attorney general of the state of Washington, state officials discussed how they would handle a variety of scenarios. What might happen if the F.B.I. showed up, demanding election materials or equipment? What if federal troops or agents were deployed in the country in ways that could intimidate voters or disrupt the election? What if President Trump tried to declare an election-related national emergency?

“The sad reality now is that the federal government is our biggest concern,” Mr. Brown said, adding, “It used to be that the Department of Justice was our No. 1 partner, helping states prepare for election-related issues.”

The Trump administration has not explicitly threatened to make any such moves, and a White House spokeswoman dismissed the Democratic efforts, arguing that the party should instead focus on passing tighter voting laws.

But Mr. Trump, who tried to overturn the results of the 2020 election, told The New York Times this year that he regretted not seizing voting machines after that contest. In his second term, he has appeared increasingly eager to use the federal government’s investigative, prosecutorial and legislative powers to influence how elections are run. His prime-time speech to the nation last week, fanning false claims of election fraud, raised new concerns about possible federal interference in the midterms.

This week, Mr. Trump and his allies seized on reports that roughly 400 noncitizens had cast ballots in New Jersey, after about 6,600 residents had been improperly registered to vote because of a 2023 software error at the Motor Vehicle Commission. (The state’s Democratic governor said what happened was “unacceptable.”)

But Mr. Trump has recently made much broader claims, which remain unsubstantiated, about hundreds of thousands of noncitizens voting illegally in four states. A letter from the Homeland Security Department, sent to one of the states and obtained by The New York Times, indicated that the data cited by Mr. Trump was an initial estimate and was probably highly inflated.

The election security meeting in May was part of a broader effort among Democratic secretaries of state and attorneys general to increase their coordination across the country ahead of the midterm elections.

They are creating two groups to formalize these partnerships: the AGSOS Election Protection PAC, which will work to raise money and elect Democrats to each office, and AGSOS Election Protection Action, a policy arm. The effort is an outgrowth of the existing campaign arms for the national groups representing each office, the Democratic Association of Secretaries of State and the Democratic Attorneys General Association.

“By formalizing this partnership between attorneys general and secretaries of state, we have created a high-functioning hub where other organizations can coordinate actions to protect election results up and down the ballot,” said Sean Rankin, the president of the Democratic Attorneys General Association.

While the holders of the two offices often work closely together in a single state, a top election official in one state will rarely work with an attorney general from another. Democrats say that creating a national network of these two offices is necessary given Mr. Trump’s actions.

“We will use all the tools at our disposal to fight Donald Trump and protect our voting rights,” Cisco Aguilar, the Nevada secretary of state and the chair of the Democratic Association of Secretaries of State, said in a statement.

Abigail Jackson, a White House spokeswoman, suggested that Democrats should be trying to pass the SAVE America Act, a stalled bill of voting restrictions that Mr. Trump has called his top priority.

“If Democrats really cared about securing our elections, they would pass the SAVE America Act, which includes common-sense election integrity measures supported by the vast majority of Americans,” Ms. Jackson said in a statement. Those provisions include requiring a documentary proof of citizenship to register to vote, as well as strict new photo identification requirements. Many eligible voters would not be able to meet the new requirements.

Democrats have pushed back in other ways against Mr. Trump’s election moves. Democratic-led states have refused to hand over private, unredacted voter files to the Justice Department, prompting 30 lawsuits from the administration.

Democratic attorneys general were also behind litigation to block both of the president’s executive orders aimed at changing American election laws. And Democratic secretaries of state have worked to re-create federal election security programs that have been cut by the Trump administration.

But the bellicose language regarding elections from the president and his allies has Democratic state officials on high alert.

Two years ago, Mr. Brown said, efforts to “delay, disrupt, interfere” with an election “would have seemed like a joke.” Now, he added, they “are very real.”