Recent polling by Democrats shows his approval ratings have dipped dramatically as GOP fortunes have dwindled because of ongoing troubles in Iraq and a series of controversies in Washington.
In a sign of Democratic optimism, at least three possible candidates are openly threatening a challenge to Hastert. Perhaps the two most credible are state Rep. Linda Chapa LaVia of Aurora and Bill Foster, a wealthy, self-financed entrepreneur and physicist who started a company that is now the world's largest manufacturer of stage-lighting equipment.
Fueling the charge is the fact that Hastert has raised relatively little money for re-election, increasing speculation in Washington that he is contemplating retirement.
Hastert weathered repeated calls for his resignation last fall in the fallout of the Mark Foley scandal, during which many accused the then-speaker of turning a blind eye to the Florida Republican congressman's allegedly improper conduct with male congressional pages.
And while Hastert never faced a serious threat from the opposition, defeating Democrat John Laesch by a 60-40 margin, even those figures were comparatively close. Between 1988 and 2004, Hastert averaged a 71 percent margin of victory and had never dipped below 64 percent, according to figures compiled by Congressional Quarterly.
By Bret Schulte