President-elect Donald J. Trump’s demand that Senate Republicans surrender their role in vetting his nominees poses an early test of whether his second term will be more radical than his first.

Over the weekend, Mr. Trump insisted on social media that Republicans select a new Senate majority leader willing to call recesses during which he could unilaterally appoint personnel, allowing him to sidestep the confirmation process. His allies immediately applauded the idea, intensifying pressure on G.O.P. lawmakers to acquiesce.

The demand to weaken checks and balances and take for himself some of the legislative branch’s usual power underscored Mr. Trump’s authoritarian impulses. While there is no obvious legal obstacle to Mr. Trump’s request, it would be an extraordinary violation of constitutional norms. There is no historical precedent for a deliberate and wholesale abandonment by the Senate of its function of deciding whether to confirm or reject the president’s choices to bestow with government power.

Ed Whelan, a legal commentator who has supported Mr. Trump’s judicial nominees but been critical of Mr. Trump himself, sounded the alarm on Tuesday in an essay for the conservative National Review. The once and future president appeared to be contemplating “an awful and anti-constitutional idea,” he wrote.

Recess appointees who take office without Senate confirmation wield the full powers of their offices until the end of the next Senate session. Each congressional session typically lasts a year, so anyone who receives a recess appointment from Mr. Trump in early 2025 could remain in office until the end of 2026.

The Constitution normally requires the president to obtain the Senate’s consent to appoint top officials to the executive branch, in part to prevent the White House from installing unfit people to high office.