By late winter or early spring, he said, the conflict could be settled, which would probably put U.S. businesses in more of a spending mood.
Friday's White House shake-up also could have a positive effect on the market, analysts said, because O'Neill was seen as a potential impediment to tax cuts and other fiscal stimulus measures.
"We've had a lot of monetary stimulus from the Federal Reserve cutting interest rates," Adelman said, noting that the Fed has slashed its benchmark interest rate to a four-decade low of 1.25%.
"What was missing was fiscal stimulus, and now we're going to get some."
One proposal that could give investors and the economy a boost, he said, is the elimination of "double taxation" on dividends, which are taxed as income when corporations record profit, then taxed again if distributed to shareholders in dividend form.
Such a move could send dividend yields, already on the rise, still higher, making stocks more attractive to investors.
A separate proposal to increase the amount of realized capital losses that can be written off against income -- currently $3,000 -- could boost consumer spending as well, Adelman said.
The Fed, which cut its benchmark interest rate by half of a point at its Nov. 6 meeting, isn't likely to notch the rate any lower when it gathers Tuesday, analysts say.