President Bush's agenda, as outlined in his State of the Union, is certainly ambitious. You may think that the president's success enacting it depends on how many votes he can round up in Congress. This is the standard way of viewing the political process, but it leaves out a constituency that may play the most important role. I'm talking about Wall Street bond traders.

Remember, the bond traders were the ones who forced Bill Clinton to scale back his ambitious plan for public investments in education and health care. They even turned Clinton into a deficit hawk. I saw it with my own eyes. The same bond traders may force George W. Bush to back down on his plans, too.

You see, Wall Street is divided right down the center lane. On the equity side of the street are the buyers and sellers of securities in brokerage firms and mutual fund companies. They're all for the Bush agenda because it will put more money in their pockets. Not only will they get more tax cuts on unearned income, but they also stand to rake in hundreds of millions in management fees on all those privatized Social Security accounts.

But on the other side of Wall Street are the bond traders, and they think differently. They're beginning to worry about the size of the deficits likely to result from Bush's plans, just like they worried about Clinton's potential deficits. They've heard estimates of the trillions of dollars the government will have to borrow over the next decade in order to privatize Social Security, not to mention making Bush's tax cuts permanent.

All the borrowing will create a deluge of new Treasury securities on the market. This will put extra pressure on interest rates because there's only a limited amount of savings out there to be borrowed -- and it'll push bond prices down.

The White House is telling bond traders not to worry because the extra borrowing will be paid back in 30 to 60 years when Social Security benefits are cut. But that may not convince the bond traders. After all, the extra debt will be added very soon, and it must be repaid. On the other hand, the promise to cut benefits three decades from now is just a promise. Who knows whether it will be kept? Thirty years from now, the politicians who have to impose those painful cuts might just back down.

So watch carefully, folks. If and when bond traders believe the president's plan is likely to pass, the value of Treasury bonds could plunge and interest rates will skyrocket. Mark my words: Even a hint of panic in the bond markets will be enough to kill the president's agenda for good.

Robert B. Reich is co-founder of The American Prospect. A version of this column appeared on Marketplace.