While some market commentators are saying that the 1.1 percent decline of the S&P 500 Monday and Tuesday, presages a major drop, CNBC contributor Ron Insana disagrees.

"The bears are making their case, but I'm not convinced it's their time yet," he writes in a commentary for CNBC.

"I don't believe this bull market is over."

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Insana sees the following factors helping to sustain the five-year-old bull market:

• A friendly Federal Reserve
• A new energy revolution
• A manufacturing renaissance in the United States
• Technological innovation
• A real estate recovery.

As for the Fed, while some economists recently pushed forward their forecasts of when the central bank will raise rates, Insana doesn't see it.

"In my view, job growth has yet to produce the type of wage inflation that can lead to a wage/price spiral," he explains.

To be sure, stocks may soon endure a correction, Insana notes. "However, I will use the opportunity to add to selected positions."

And he says he won't give up on the bull market until "interest rates rise, Fed policy changes, or an unexpected war draws in the U.S."

Others are optimistic about stocks too. "The market can go down, but it won't stay down," John Manley, chief equity strategist at Wells Fargo Funds Management, tells Bloomberg.

"The fact that the market is still questioning all these things that are going on is a very healthy sign. I still think the Fed is going to be more concerned about making absolutely sure that the U.S. economic recovery is under way and staying underway."

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