Washington (CNN) -- House Speaker Nancy Pelosi predicted Thursday that tax cuts for middle class Americans would be extended by Congress.

Pelosi told her weekly news conference that she supports President Obama's proposal to maintain the reduced tax rates for people earning $250,000 a year or less, while allowing the Bush-era tax cuts to expire for those who make more.

Thirty-one House Democrats, most of whom face tough re-election bids this fall, have signed a letter to Pelosi and House Majority Leader Steny Hoyer urging them to extend expiring tax breaks for all income levels, including the wealthy.

However, Pelosi said the Obama plan makes the most sense.

"The only thing I can tell you is that the tax cuts for the middle class will be extended in this Congress," Pelosi said.

Republicans also say the tax cuts, introduced by President George W. Bush in 2001, should be kept in place for everyone.

With the midterm elections less than two months away, Democratic leaders have not yet decided whether they will schedule a vote on the legislation before voters go to the polls.

House Minority Leader John Boehner, R-Ohio, said Thursday that he has urged Pelosi to allow an "honest up-or-down vote" on extending all the Bush tax cuts. Anything less, he said, is "unacceptable."

Boehner said earlier this week that while he wants to extend tax cuts for all Americans, he would back Obama's plan if it is the only option available.

Boehner pushes extension of all Bush tax cuts

Americans appear divided on the issue. Most -- but not all -- polls conducted over the last month indicate that a slight majority don't want tax breaks for the wealthiest income earners to be extended.

According to a new New York Times/CBS News survey, 53 percent say the Obama administration's proposal to let tax cuts for households earning $250,000 or more per year expire is a good idea, with 38 percent saying it's a bad idea.

In a CNN/Opinion Research Corp. national poll conducted in early August, three in 10 said that the Bush-era tax cuts should be continued for all Americans, with a little more than 50 percent saying those tax cuts should be continued only for families who make less than $250,000 a year, and nearly one in five believing the tax cuts should expire for all Americans.

However, in an Ipsos/Reuters poll also conducted last month, 49 percent said tax cuts for all should be extended, while 31 percent said they should expire for the wealthiest Americans and 15 percent called for an end to the tax cuts for everyone.

See results from more polling on tax breaks

The letter from House Democrats to Pelosi and Hoyer -- written by Reps. Jim Matheson of Utah, Melissa Bean of Illinois, Glenn Nye of Virginia and Gary Peters of Michigan -- says that after listening to economists, small businesses and families over recent weeks these lawmakers are concerned that "raising any taxes right now could negatively impact economic growth."

"We believe in times of economic recovery it makes good sense to maintain things as they are in the short term, to provide families and businesses the certainty required to plan and make sound budget decisions. Providing this certainty will give small businesses, the backbone of our economic recovery, confidence and stability," the lawmakers wrote.

CNN reported that the four authors were circulating a draft of the letter earlier this week. But with more than 30 Democrats now signed on to the final letter, Democratic leaders will face increasing pressure to address the concerns of these members.

Republican congressional leaders have been making similar arguments, pushing for a two-year freeze on all current tax rates.

On Wednesday, Hoyer told reporters he could consider proposals to extend tax cuts for higher wage earners, but he also stressed his strong support for just renewing the middle-income tax breaks.

Later Wednesday, Hoyer released a statement noting he was simply saying he was willing to talk to others about their positions.

"Unfortunately, the reports of my answer implied a willingness to support an extension of Bush policies," he wrote. "That is incorrect."

CNN's Dana Bash and Paul Steinhauser contributed to this report.