What if I told you that a prominent global political figure in recent months has proposed: abrogating key features of his government's contracts with energy companies; unilaterally renegotiating his country's international economic treaties; dramatically raising marginal tax rates on the "rich" to levels not seen in his country in three decades (which would make them among the highest in the world); and changing his country's social insurance system into explicit welfare by severing the link between taxes and benefits?

The first name that came to mind would probably not be Barack Obama, possibly our nation's next president. Yet despite his obvious general intelligence, and uplifting and motivational eloquence, Sen. Obama reveals this startling economic illiteracy in his policy proposals and economic pronouncements. From the property rights and rule of (contract) law foundations of a successful market economy to the specifics of tax, spending, energy, regulatory and trade policy, if the proposals espoused by candidate Obama ever became law, the American economy would suffer a serious setback.

To be sure, Mr. Obama has been clouding these positions as he heads into the general election and, once elected, presidents sometimes see the world differently than when they are running. Some cite Bill Clinton's move to the economic policy center following his Hillary health-care and 1994 Congressional election debacles as a possible Obama model. But candidate Obama starts much further left on spending, taxes, trade and regulation than candidate Clinton. A move as large as Mr. Clinton's toward the center would still leave Mr. Obama on the economic left.

Also, by 1995 the country had a Republican Congress to limit President Clinton's big government agenda, whereas most political pundits predict strengthened Democratic majorities in both Houses in 2009. Because newly elected presidents usually try to implement the policies they campaigned on, Mr. Obama's proposals are worth exploring in some depth. I'll discuss taxes and trade, although the story on his other proposals is similar.

First, taxes. The table nearby demonstrates what could happen to marginal tax rates in an Obama administration. Mr. Obama would raise the top marginal rates on earnings, dividends and capital gains passed in 2001 and 2003, and phase out itemized deductions for high income taxpayers. He would uncap Social Security taxes, which currently are levied on the first $102,000 of earnings. The result is a remarkable reduction in work incentives for our most economically productive citizens.