Then-deputy national security adviser Ben Rhodes speaks at a White House briefing in 2016. (Carolyn Kaster/AP)

Voters were undeterred by the 2016 cries of alarm from Democrats — and some Republicans — that Donald Trump was unqualified to be commander in chief, but a group of Democrats is betting Trump’s record in office will push national security issues to the fore in the 2018 midterms and the next presidential election.

A group of mostly young veterans of President Barack Obama’s administration and Hillary Clinton’s 2016 presidential campaign is launching a political strike force aimed at countering Trump and Republicans on national security.

“We decided, essentially, this is an emergency moment and that there was a need to pull together the national security community on the progressive side to counter Trump’s policies and put forward an alternative” in this midterm year, said Ben Rhodes, one of the founders.

The group, National Security Action, is more expressly political than many Democratic-leaning think tanks and policy shops, but it will not endorse candidates or make political donations, Rhodes and others said.

The idea is to provide Democratic candidates, lawmakers and policy organizations with a foreign policy tool kit — everything from talking points to legal and policy expertise to campaign surrogates — as they oppose President Trump, said Rhodes, a deputy national security adviser for Obama.

Some 500 former officials and campaign veterans have agreed to participate as speakers, writers or on-call experts for candidates, think tanks or advocacy organizations, Rhodes said.

“We’re a temporary organization. Our hope is to be out of business in three years,” Rhodes said in an interview.

Co-founder Jake Sullivan, an adviser to Clinton during her 2016 campaign and earlier when she was secretary of state, said the group will also advise Democrats in congressional oversight of Trump.

“We think that Trump is already signaling ways in which he’s going to try to shape the national security debate heading into the fall and that it’s going to be part of his political strategy,” Sullivan said.

“You saw that in the way he tried to link personal security and national security, between terrorism” and immigration, he said.

The group expects to help Democratic candidates use Trump’s first-year record against all Republicans as Democrats attempt to take control of the Senate and House in the November congressional elections, Rhodes and other organizers said.

The group will assist Democratic challengers and Democrats contesting in open seats and won’t pick favorites in primaries, organizers said. The group is expected to soon announce several key races it will focus efforts on this year.

“There was a need for connective tissue,” said former senior State Department official Wendy Sherman. “It’s connecting all the progressive groups and citizens that are very concerned about America’s place in the world, about our leadership in the world, and that are very concerned about the institutions that ensure the rule of law in the world and our security and prosperity.”

She cited climate change and Trump’s withdrawal from the Paris accord as one issue with deep national security implications and the heightened rhetoric and tension surrounding North Korea’s nuclear program as another. The group will also focus on cyberthreats in general and, in particular, Russian election interference and Trump’s response, Sherman and others involved in the effort said.

“It’s not easy to talk about national security issues” in local elections, Sherman said. “Most often, people don’t see it as having anything to do with their daily lives, but here we have climate change, North Korea and other issues that have everything to do with people’s lives. I think people are much more aware of it” now than in 2016.

Trump says he has boxed in North Korean leader Kim Jong Un with a mixture of new sanctions and the threat of U.S. military action, but Democratic critics say Trump has taunted the unpredictable leader and raised the risk of war.

On Iran, Trump claims he is forcing a reconsideration of Obama’s landmark 2015 nuclear pact, which Trump calls weak and ineffectual. Democrats say they can show how Trump’s actions have frayed alliances and reintroduced a near-term threat of an Iranian nuclear bomb.

Sherman was among the well-known national security figures who backed Clinton and seconded the Democratic nominee’s argument that Trump was unfit. It was a theme that sounded better in theory than in practice against Trump’s powerful populist message, as many Democrats now concede.

Clinton banked that her tenure as secretary of state and even her reputation as a foreign policy hawk — which had hurt her with the Democratic base in 2008 — would help her against Trump.

“He is not just unprepared — he is temperamentally unfit to hold an office that requires knowledge, stability and immense responsibility,” Clinton said as she began to make the national security case against Trump in June 2016.

“This is not someone who should ever have the nuclear codes,” she said, “because it’s not hard to imagine Donald Trump leading us into a war just because somebody got under his very thin skin.”

Clinton’s campaign even hoped her credentials would persuade some national-­security-minded Republicans and independents to vote for her rather than see Trump win the White House.

In the end, national security issues were far down the list of reasons that voters said moved them to pick Trump. The novice Republican politician had an ear for economic anxieties and concern over immigration that helped build a “security” narrative that was more direct and personal than the themes Clinton articulated.

Trump has kept that narrative going in office, and it has proved effective in keeping Trump’s political base on board, Sullivan said Tuesday.

Sullivan and Rhodes asserted, however, that there are many examples of Trump reneging on the promises he made to voters, including to disentangle the United States from Middle East wars. He has continued or expanded the fights in Iraq and Syria without a clear mission, Rhodes said.

Jen Psaki, a senior Obama adviser who also served as State Department spokeswoman, said Trump’s governing record “is worse than we thought” and provides Democrats ammunition they didn’t have in 2016.

“Now, 15 months later, there’s a record to look at,” Psaki said. “It’s now played itself out, and the warnings have come true and then some.”

Typically, national security issues are less important voting motivators for Democrats than for Republicans, except in times of unpopular wars. Nonetheless, the new group plans to try to amplify a Democratic message that Trump is erratic and untrustworthy in foreign policy.

A CNN poll in October found that Republicans were more likely than Democrats to say national security was one of the nation’s top problems (29 percent vs. 16 percent), while Democrats were more likely to point to health care, by roughly the same margin.

A Pew Research survey last fall suggested that since Trump’s election, the Democratic Party had reversed Republicans’ advantages in trust to handle foreign policy and terrorist threats, although other surveys through December found that Republicans still held an advantage on some of those issues or that the public was split.

Overall, however, national security is a weak spot for Trump, with many worrying that he could take military action rashly.

This type of concern is widespread among Democrats. In January, a Washington Post-ABC News poll found 60 percent of Americans said they do not trust the president to handle his authority to launch nuclear weapons responsibly (38 percent trusted him), including 52 percent who said they are very or somewhat concerned he might launch a nuclear attack without justification. Among Democrats, 90 percent do not trust him with nuclear authority and 74 percent are concerned that he might launch an unjustified nuclear attack.

CNN’s January poll found 35 percent approved of Trump’s handling of foreign affairs, similar to where he has stood for six months but lower than the 49 percent who approve of his job on the economy.

Scott Clement contributed to this report.