As for energy policy, the president's cap-and-trade plan for CO2 would ensnare a vast network of covered sources, opening up countless opportunities for political manipulation, bureaucracy, or worse. It would likely exacerbate volatility in energy prices, as permit prices soar in booms and collapse in busts. The European emissions trading system has been a dismal failure. A direct, transparent carbon tax would be far better.

Moreover, the president's energy proposals radically underestimate the time frame for bringing alternatives plausibly to scale. His own Energy Department estimates we will need a lot more oil and gas in the meantime, necessitating $11 trillion in capital investment to a...

As for energy policy, the president's cap-and-trade plan for CO2 would ensnare a vast network of covered sources, opening up countless opportunities for political manipulation, bureaucracy, or worse. It would likely exacerbate volatility in energy prices, as permit prices soar in booms and collapse in busts. The European emissions trading system has been a dismal failure. A direct, transparent carbon tax would be far better.

Moreover, the president's energy proposals radically underestimate the time frame for bringing alternatives plausibly to scale. His own Energy Department estimates we will need a lot more oil and gas in the meantime, necessitating $11 trillion in capital investment to avoid permanently higher prices.

The president proposes a large defense drawdown to pay for exploding nondefense outlays -- similar to those of Presidents Carter and Clinton -- which were widely perceived by both Republicans and Democrats as having gone too far, leaving large holes in our military. We paid a high price for those mistakes and should not repeat them.

The most recent case, of course, was the government's meddling in the housing market to bring home ownership to low-income families, which became a prime cause of the current economic and financial disaster.

On the growth effects of a large expansion of government, the European social welfare states present a window on our potential future: standards of living permanently 30% lower than ours. Rounding off perceived rough edges of our economic system may well be called for, but a major, perhaps irreversible, step toward a European-style social welfare state with its concomitant long-run economic stagnation is not.

Mr. Boskin is a professor of economics at Stanford University and a senior f...

The most recent case, of course, was the government's meddling in the housing market to bring home ownership to low-income families, which became a prime cause of the current economic and financial disaster.

On the growth effects of a large expansion of government, the European social welfare states present a window on our potential future: standards of living permanently 30% lower than ours. Rounding off perceived rough edges of our economic system may well be called for, but a major, perhaps irreversible, step toward a European-style social welfare state with its concomitant long-run economic stagnation is not.

Mr. Boskin is a professor of economics at Stanford University and a senior fellow at the Hoover Institution. He chaired the Council of Economic Advisers under President George H.W. Bush.