Will Trump’s Midterm Convention Help or Hurt Republicans? 5 Things to Watch.

The two-day convention that Republicans are holding on Wednesday and Thursday is the first of its kind in nearly 50 years. President Trump has summoned members of his cabinet and a few dozen of the party’s top candidates to Dallas to celebrate him and promote his administration’s accomplishments heading into midterm elections in which he is not on the ballot.

If Mr. Trump were popular, this might be seen as helpful for fellow Republicans, but polls show that many Americans have grown unhappy with his leadership on domestic, foreign and economic issues. This event is perhaps his last big opportunity before November to convince Americans that he has the country on the right track.

Republicans, despite some private grumbling, have mostly gotten publicly on board with Mr. Trump’s convention extravaganza. But do not expect significant critiques of his administration from the stage in Texas.

Here are five key questions for the president’s Republican midterm convention:

Is a two-day Trump rally helpful for Republicans?

Mr. Trump’s approval ratings are quite bad — 38 percent in the New York Times polling average.

In a pre-Trump era, candidates in battleground races would not want to tie themselves to a president with such poor numbers. But Mr. Trump has positioned himself as the sun of the Republican Party’s solar system, and the party’s midterm candidates drift away from him at their own political risk.

Mr. Trump has immense financial power over Republican campaigns — “this is my money that I control,” he said last week of his super PAC’s hundreds of millions of dollars. He has also shown little inclination to allow fellow Republicans to oppose his agenda.

Just a few of the convention speakers announced by the Republican National Committee are in battleground races. They include three of the party’s top Senate candidates: Senator Jon Husted of Ohio, former Representative Mike Rogers of Michigan and Michael Whatley, a former R.N.C. chairman running in North Carolina.