DENVER – If a president could improve the economy, he would. If a president could prevent the economy from going into the tank, he would. Just ask Jimmy Carter.

If, as president, Carter could have dictated an interest rate in the single digits, he would have – rather than enduring the 16 percent and 18 percent and 20 percent the nation experienced leading up to the president’s bid for re-election.

If, as president, Carter could have waved a wand and eliminated the gasoline lines that tormented American motorists, he would have – rather than enduring the humiliation and frustration of watching the national news every night, showing video of cars lined up, seven lanes across, around the corner and down the street waiting to top off their tanks.

But, despite John Kerry’s notion of reality, there is no magic wand hidden in the bottom drawer of the president’s desk in the Oval Office.

For one thing, there is a Congress in our form of government. For another thing, we live in and abide by a capitalist system, which means the political system is subject to a market economy. And for another thing, as Kerry is so fond of reminding us on other occasions, we live in a global village.

When we hiccup, Japan and Brazil and Egypt and Germany and England lurch. And when the European Union hiccups, we lurch. A president has no miraculous elixir to stop the hiccups, despite the snake-oil peddled by Kerry and his supporters.

To examine this in light of the 2004 campaign, now mercifully just days from its demise, let’s consider three major factors that have influenced the economy in the last four years:

•The dot.com crash of 2000 didn’t develop on George Bush’s watch. If Bill Clinton could have prevented it from happening, he had a moral obligation to do so. He didn’t – because, of course, he couldn’t. He couldn’t find the magic wand in his desk drawer.

•The corporate multibillion-dollar fraud/greed scandals that wracked the economy, from Enron to Adelphia to Qwest, developed on Bill Clinton’s watch. If he could have prevented it, maybe he would have. But he couldn’t – even if he had wished to, at the agony of many of his campaign contributors.

In my own home state, Colorado, the telecommunications company Qwest, accused in a $3.8 billion fraud case, has settled for a fine of $250 million. The roots of the fraud, likened by the SEC to a heroin addiction, extended well back into the Clinton administration and was exposed under Bush.

•The crash of 9/11. Need I say more? When the twin towers of the World Trade Center collapsed, so did the American and international economies. And we are still feeling the effects.

Yet we have so soon forgotten, after only three years. In the months after 9/11, the travel industry was in a state of stagnation. Today it is walking and talking and hiring people. Consumers stopped buying wide-screen TVs, and fancy refrigerators and new houses in the suburbs. Automakers were paying consumers to buy their products.

Today, a couple of years after suffering one of the most severe attacks on the U.S. economy, the stock market is thriving, corporate scandals have been reduced to prosecution cases, employment is rebounding and people are no longer afraid to buy a ticket on an airplane or a bus. Even the cruise-line industry, despite a horrific hurricane season, is happy with sales.

No president can control the economy in a market-driven system. If you want a leader who has an iron grip on the economy, move to Cuba – or believe in John Kerry.

Under some of the worst conditions in American history, George W. Bush has been a good steward. Now is no time to change course and go back to the era of appeasement, Jimmy Carter and John Kerry’s promise of a magic wand.

John Kerry likes to have us think that he, as president, would have control of the American economy. Yet he will never admit that al Qaeda was more in control of the American economy in 1996-2001 than any president ever has been.

The United Nations didn’t do much to protect us then, and it has even less power than the president – even the omnipotent John Kerry.