The stock market may be holding up admirably well in the face of many uncertainties, but the risks just won’t quit popping up. One of the newest is the threat of a political move to impeach President Bush if the Democrats can achieve substantial gains in the midterm elections and recapture control of the House and Senate.

This impeachment scenario, which may strike some as far-fetched, is on the mind of a well-regarded Boston investment strategist, Bill Rhodes, the head of Rhodes Analytics and a former Merrill Lynch strategist who doles out investment advice to a lineup of institutional clients with roughly $1 trillion in assets.

November’s midterm elections are inching closer, and the message from one political pundit after another is that if they were held today, the Democrats would stand a good shot of regaining control of the House and Senate. The chief reasons are the public’s growing opposition to the war in Iraq and the president’s sliding ratings in the polls.

Such a power shift in Congress — which, of course, at this point is a very big if — could have distinctly negative market implications and should not be taken lightly, Mr. Rhodes cautions.He says there could be an active move by the Democrats to impeach the president if they were to take control of Congress. While he says he’s uncertain how such an effort would play out, he argues that there are “some Democrats who really want to go through the process, and there’s a significant possibility that the process could take place.”

If he’s right, Mr. Rhodes says the country “would be going through an ugly process,” which would include accusations, mudslinging, and possible investigations. As far as Wall Street goes, he says any impeachment move would be a mighty distraction for the market. In response, he would expect a sell-off, perhaps a dramatic one.

In any case, Mr. Rhodes — the very first pro I’ve come across who has raised the impeachment issue as a significant risk for the stock market — sees a lot of trouble for the Republican Party. “We’re approaching the fifth year of an unprovoked war that began on September 11, 2001, there are no clear signs that would constitute a victory, and people are getting restless.” He points out that World War II lasted four years.

To date, two American presidents have been impeached — Andrew Johnson in 1868 and Bill Clinton in 1998. Neither, though, was convicted in their Senate trials.

Given the number of Bush haters in Congress, a financial adviser based in Cleveland, Edward Dannes, says he agrees that a big Democratic win in the midterm elections could trigger an impeachment effort. On the face of it, he says, the idea seems off the wall, but just the thought it could happen would be sufficient to unnerve the financial markets. “I’m not sure such concerns would drive stock prices lower, but I do think they might tend to impede their ability to move higher, but only if there’s a legitimacy to such a possibility,” he says.

Mr. Dannes, whose firm, the Dannes Group, focuses on clients with minimum seven-figure net worths, says he’s been asked on a number of occasions recently about the potential impact of the impending elections, though no one has raised the impeachment issue. His view: Wall Street would react poorly to a Republican loss of the House and Senate, considering that it believes the current congressional makeup is strongly pro-business.

One of the West Coast’s more successful day traders, Arnold Silver, a Republican, ridicules the idea of a Bush impeachment, saying he doubts such a move would ever get off the ground. “The president is trying to ensure the security of America; that’s not an impeachable offense,” he says. “Did he make mistakes along the way? Who doesn’t make mistakes?”

Suppose he’s wrong and there is a meaningful impeachment move? Mr. Silver says he believes the market would undergo serious weakness, and in the event of any such development, “the market should be the least of anyone’s concerns.”

A professor of political science at the University of Virginia, Larry Sabato, says he thinks there’s a 50-50 chance the Democrats will take the House in the November elections and a 45% chance they’ll snare the Senate. If they do take the House, he says some liberal member will almost certainly file articles of impeachment. However, the House minority leader, Nancy Pelosi, has made it clear she wouldn’t support such an effort. “And without her,” Mr. Sabato says, “it just won’t fly.”