U.S. President Donald Trump on Monday described Tuesday’s midterm elections as “the most important election of our lifetime,” making a final appeal to mobilize his supporters as Democrats seek to regain control of Congress.

“We are on the eve of the midterm elections, which I believe are the most important of our lifetime,” the president said during an address in Washington. He also devoted part of his speech to the renovation of a large pool in the U.S. capital, in front of which he was speaking.

In his final remarks before the vote, Donald Trump also sharply criticized his Democratic opponents, claiming they had “put forward the most extreme and dangerous slate of candidates in the history of the United States.”

A major political test

The elections represent a major political test for the Republican president, whose party is seeking to defend its majorities in Congress. Democrats, meanwhile, hope to regain control of both the House of Representatives and the Senate, amid growing voter concerns over the cost of living.

Mr. Trump nevertheless acknowledged that sitting U.S. presidents generally face difficulties in midterm elections, which are held halfway through a presidential term.

“For some reason, the incumbent president does not win the midterms,” he said, before adding: “But we have done everything we can to make it happen.”

A nationwide vote

Tuesday’s midterm elections will determine all 435 seats in the House of Representatives and approximately one-third of the seats in the Senate. The outcome will shape the balance of political power in Congress for the second half of the presidential term.