The White House has toned down its earlier optimism about the midterm elections and is now worried that Democrats could lose control of both houses of Congress, administration officials say, Reuters reports.

Recent polls have shown that Democrats, who once had a solid lead in some Senate races, are on a knife edge, and success in the Senate race now leans toward Republicans as high inflation persists.

The House victory that Biden and some allies and advisers predicted for Democrats earlier this year is leaning decidedly in favor of Republicans, analysts including FiveThirtyEight say.

Losing control of one or both chambers of Congress will greatly affect the next two years of Joe Biden's presidency, as Republicans are expected to block family leave, abortion, police work and other Biden priorities while pushing new laws limiting immigration and spending, using the debt ceiling as leverage.

Republicans are also expected to begin investigating Democratic spending, as well as the business dealings and personal life of President Hunter's son. Some lawmakers say they hope to impeach Biden, members of his cabinet or Vice President Kamala Harris.

According to a source, the Democrats' chances of retaining control of the Senate are estimated at 50-50.

In May, Biden predicted that his Democratic colleagues would succeed in both the House and Senate, but last week he acknowledged that the race had tightened.

The White House, being realistic, has publicly stuck to a message of hope.

The president and his advisers believe we stand a good chance of keeping both chambers and are focused on doing everything we can to capitalize on how much Republicans are playing into our hands, including saying that their top priority is to worsen inflation with tax breaks for the rich, one Biden adviser said in response to a Reuters report.

Former and current advisers say the White House is preparing for any obstacles or investigations that may arise.

Earlier this year, the White House hired Richard Sauber as special counsel to prepare for any investigations, but additional hires and personnel changes are on hold until the election results are announced, a source familiar with the situation said. He added that internal divisions within the Republican Party mean these lawmakers may have problems with what to focus on.