WASHINGTON — Republican lawmakers in the House are hurtling toward a collision over immigration, raising the prospect of a divisive and uncomfortably public intraparty fight just five months before November’s midterm elections.

And party leaders are running out of time to stop it.

In the face of a rebellion from moderate members, who are on the brink of forcing a series of immigration votes over the objections of Speaker Paul D. Ryan, Republicans will meet privately on Thursday morning to discuss the issue.

“Our members are earnest and sincere in trying to understand each other’s perspectives,” Mr. Ryan told reporters on Wednesday, adding, “I really do believe that there is a sweet spot here.”

At the center of their discussions is the fate of hundreds of thousands of young immigrants brought to the country illegally as children — known as Dreamers. Here’s a guide to the impending showdown.