One analysis concludes that last week's sharp three-day market surge can only mean that Wall Street is banking on a victory from Republican Mitt Romney.

That's the logical interpretation one can draw from a rally amid conditions that otherwise would demand a selloff, Morgan Stanley chief U.S. equity strategist Adam S. Parker said in an analysis that asserts there is no other reason now to like stocks than a Romney win.

"The problem is that it’s impossible to be bullish and right for the right reasons," Parker said in a note to clients in which he reiterated his 2012 price target for the Standard & Poor's 500 at 1,214, which would mark a 12 percent drop from the current level.

"Nearly every day someone expresses surprise that our base case is for the equity market to be down by 10-15 percent. Why is this so hard to believe? The market has had eight 10 percent down moves in the last 12 years," Parker said. "We think a better question is why more people don’t forecast that the next 10-15 percent move is down than up?"

Parker cites weak earnings and the likelihood that central bankers won't be able to continue to save the day as bolstering the case against equities. The near-zero interest rate policies from the Federal Reserveand now the European Central Bank, in fact, are weakening the outlook for stock multiples, he said.

The conclusion Parker draws is that investors are betting that Romney will unseat President Obamaand bring a more business-friendly environment to the White House.

"At the end of the day, we are not really worried that Europe is going to be 'solved' or that its economy will strongly grow. We also don’t think strong corporate profitability relative to expectations will save the day," he said.

"To us, the biggest bull case for US equities is based on the huge cash balances and the potential belief that they will be more actively and productively deployed. The biggest possibility here would be Romney winning the presidential election."

The conclusion, though, is not completely supported, either by past or present conditions.

Historically, moves higher in the market usually mean the incumbent president is likely to win, while sell-offs simply indicate the challenger is favored, according to research from S&P/Capital IQ.