LAS VEGAS — Leaving behind the chaos he sowed in Washington with his shifting immigration policies, President Trump visited his second midterm battleground state of the week on Saturday to deliver the blunt message he has repeated at rallies for weeks: “We need more Republicans.”

For a few hours, at least, Mr. Trump put the intricacies of governing in his rearview mirror, attending a Republican convention on the outskirts of the city here, a private event for Senator Dean Heller and a tax-focused round-table discussion.

Back in the capital, some government officials are reeling over directives to enforce — and, as of Wednesday, reverse — Trump administration policies that resulted in the separation of some 2,300 children from their parents at the border. Congressional Republicans, stalled by dysfunction and flummoxed by the president’s back-and-forth orders, are unsure how to proceed with a legislative fix before November.

Mr. Trump, seemingly unconcerned by the clashes, has instead focused on deploying an old campaign tactic: inundating the public with conflicting messages, then hitting the trail to speak to supporters who are more focused on winning the state and sharing his grievances about the Democrats.