As the United Auto Workers strike enters its fifth day, Democratic politicians are moving to show solidarity with the strikers — and so are some Republicans, as the GOP seeks to exploit tension between the Democrats’ support for electric vehicles and unions.

Ahead of the strike, a Gallup survey found that 75 percent of Americans “side with workers” in the UAW dispute with the Big Three, while 19 percent side with the employers.

Over the weekend, elected officials, including top Democrats, issued statements aligning themselves with the union and visiting picket lines across the Midwest.

In a set of short remarks at the White House, President Biden said that “workers deserve a fair share of the benefits they helped create,” and that he was sending surrogates to Michigan to “ensure record corporate profits mean record contracts for the UAW.”

“Over generations, autoworkers sacrificed so much to keep the industry alive and strong, especially through the economic crisis and the pandemic,” Mr. Biden said.

Democrats in the upper chamber, including Senators Fetterman, Brown, and Peters, also expressed support for the union. All made the trip to picket lines in Michigan. Senator Sanders endorsed the UAW’s demand of a four-day workweek, telling Newsweek that there should be a “serious discussion” on the issue.

“This union’s strike is important not just for the UAW but for American workers all across the country as well,” Mr. Peters said. “These are folks who sacrificed over the years to make sure that these companies were successful and now that they’re very profitable it’s time to share those profits.”

Aside from top national Democrats, members of the lower chamber such as Congresswoman Elissa Slotkin of Michigan, Congresswoman Summer Lee of Pennsylvania, and Congresswoman Cori Bush of Missouri expressed support for the striking union members, as did numerous state-level officials. 

At the same time, some Republicans, who historically have been anti-union, also sought to align themselves with union members. Among them was President Trump, who unleashed a string of posts on Truth Social accusing Mr. Biden of betraying union members.

“The United Autoworkers are being sold down the ‘drain’ with this all Electric Car SCAM,” Mr. Trump said. “They’ll be made in China, under Crooked Joe’s CHINA FIRST POLICY. AUTOWORKERS, VOTE FOR TRUMP – I’LL MAKE YOU VICTORIOUS and RICH.”

Mr. Trump also called on union members to disavow the union’s president, Shawn Fain, if he doesn’t endorse the presidential candidate, adding that supporting Mr. Biden would leave them  “JOBLESS and PENNILESS WITHIN 4 YEARS.”

Mr. Fain was the first UAW president elected through a popular vote, beating out the incumbent, Ray Curry, in a close election and assuming office in March. 

Mr. Fain has withheld the union’s endorsement of Mr. Biden, telling CBS News, “Our endorsements are going to be earned. We’ve been very clear about that, no matter what politician.” He added: “We expect actions, not words.”

Some of Mr. Trump’s acolytes, like Senator Vance, have also thrown in with the union members while simultaneously attacking Mr. Biden’s push for electric vehicles. Mr. Vance also accused Mr. Biden’s administration of colluding with the union to focus its strike in what he calls “deeply Republican states.” 

“The UAW’s planned strikes have targeted just three plants, including two in the deeply Republican states of Ohio and Missouri,” Mr. Vance wrote in a letter. “Only one strike affects Michigan, where the bulk of UAW members live and work. This pattern seems hardly coincidental.”

The initial facilities that the UAW tapped are all assembly plants, one for each of the Big Three. The strategy of targeting just a few of the most important plants allows for the union’s strike fund to last longer even while affecting the revenues of the strike targets.

While support for the union has not been as widespread in the GOP as it is in the Democratic Party, representatives from states with a UAW presence have expressed support, like Congressman John James, who represents a competitive district in Michigan.

“UAW workers get up early every morning and work hard for a living — that’s the Michigan way. Meanwhile, coastal elites in the Biden administration wake up and go to the couch where they’ll work from home,” Mr. James said.

While the GOP is looking to exploit the tension between Mr. Biden’s push for electric vehicles and his expressed support for unions as a pressure point, the union has not staked out an explicitly anti-electric vehicle position. Its leaders do, though, want assurances that employees who lose their jobs in the transition to electric vehicles will be supported.

“We believe in a green economy. We have to have clean water, we have to have clean air. Anyone that doesn’t believe global warming is happening isn’t paying attention,” Mr. Fain told CBS. “But this transition has to be a just transition, and a just transition means, if our tax dollars are going to finance this transition, then labor can’t be left behind.”

One of the demands of the union that has become central to negotiations is that employees at joint-venture plants, which auto manufacturers have used to exclude employees at electric vehicle plants from UAW contracts, be included in the union’s bargaining agreement.

The UAW is also demanding that the right to strike at closing plants be reinstated, citing the concern that plants that build parts only needed for traditional autos will close in the coming decades.