WASHINGTON — Mike Johnson, the Republican speaker of the House, delivered an unusually stark warning over the weekend: if his party loses control of the chamber in the 2026 midterm elections, Donald Trump could again face impeachment.

Speaking to a crowd of young conservatives at a conference organized by Turning Point USA in Phoenix, Mr. Johnson framed the midterms as an existential test not only for the Republican Party but for Mr. Trump’s presidency. “Everything is on the line in the midterms of 2026,” Mr. Johnson said, warning that a Democratic takeover of the House would lead to renewed impeachment efforts and what he described as “absolute chaos.”

The remarks marked a notable shift in tone for the speaker, who has often sought to project calm stewardship of a narrowly divided House. Instead, Mr. Johnson adopted language more commonly associated with campaign rallies, underscoring the degree to which Republican leaders are already bracing for a difficult electoral environment.

Recent polling has contributed to that unease. Surveys released in recent weeks show Mr. Trump’s approval rating declining, in some cases approaching the lowest levels recorded during his first term. At the same time, a growing share of voters say the country is on the “wrong track,” a metric political analysts frequently associate with losses for the president’s party in midterm elections.

Harry Enten, a senior data analyst at CNN, said last week that such numbers historically place the party in power at significant risk of losing House seats. “If the wrong-track numbers look anything like they do right now,” Mr. Enten said, “the Republican Party is on track to lose the House of Representatives.”

Mr. Johnson’s warning also reflected a political reality already visible on Capitol Hill. Some Democrats have made clear that impeachment remains on the table should they regain control of the House. Representative Al Green of Texas, a Democrat, introduced articles of impeachment earlier this year, though the effort was quickly tabled while Republicans retain the majority.

Under the Constitution, impeachment proceedings must begin in the House, where a simple majority can approve articles of impeachment. With Democrats currently in the minority, such efforts have little chance of advancing. But a shift in control following the midterms would dramatically change that calculus.

Mr. Johnson’s comments came amid criticism from Democrats — and some independents — that Republican leaders have struggled to offer clear explanations on a range of controversies involving the administration. In recent press conferences, the speaker has declined to comment on several issues, saying he had not yet reviewed the details or was unaware of specific developments.

Democrats argue that such responses point to a broader pattern of deference to the president. Republicans counter that the speaker is appropriately cautious, avoiding premature judgments on complex matters while Congress focuses on legislation and oversight.

At the conference in Phoenix, however, Mr. Johnson was far less circumspect. He urged young conservatives to mobilize, casting the election as a choice between Republican governance and what he characterized as a radical agenda driven by the political left. The language echoed themes that have become central to Mr. Trump’s political appeal, particularly the portrayal of Democrats as intent on dismantling traditional institutions.

Political historians note that warnings of impeachment have become a recurring feature of modern American politics. Mr. Trump was impeached twice during his first term — first over his dealings with Ukraine and later for his actions surrounding the Jan. 6 attack on the Capitol — though he was acquitted by the Senate both times. Those episodes, once considered extraordinary, have since reshaped expectations around congressional oversight and executive accountability.

Whether impeachment would again become a central feature of American political life depends largely on the outcome of the 2026 elections — and on how Democrats choose to wield power if they regain it. Some party leaders have cautioned against making impeachment a priority, arguing that voters are more focused on economic issues, health care and the cost of living.

Still, Mr. Johnson’s warning underscores the extent to which impeachment has become a mobilizing tool for Republicans, used to energize voters and frame the stakes of an election in stark terms. It also reflects the deepening entanglement between Mr. Trump’s political fortunes and those of his party, even years after his first term reshaped the Republican coalition.

As the midterms approach, the speaker’s remarks suggest that Republicans see the fight for the House not merely as a contest over legislative power, but as a referendum on the future of Mr. Trump himself — and on the balance of power between Congress and the presidency in an increasingly divided nation.