Many Americans could be hit with a big tax increase in the next two or three years despite President Barack Obama's repeated promises to shield the middle class from higher rates.

Democrats are hedging about making Obama's pledge stick for more than a year or two, setting up a major battle on a super-sensitive subject just before the November elections.

With the most sweeping tax cuts in a generation due to expire in January, the Democrats are divided over whether the government can afford to make any of them permanent — especially with voters increasingly upset over the fast-rising federal budget deficit.

Party lines are clear on part of the issue: Most Republicans want to permanently extend all the tax cuts enacted during George W. Bush's presidency, nearly $3 trillion worth over the next decade. Democratic leaders want to let the cuts for the wealthiest Americans expire.

The Democrats want to extend them for everyone else, but perhaps only temporarily, out of concern for the rising red ink. That's where Democratic lawmakers are struggling to find agreement.