As unrest is rattling the nerves of some Middle Eastern and North African countries, the United States seems eager to step into the limelight and is banging the drum for "democracy."

However, is America's high-profile intervention in that region's affairs really what it asserts is for the purpose of "promoting democracy?"

Just a look at America's track record would easily lead to an obvious conclusion: No matter it is under the excuse of "fighting terrorism" or "promoting democracy," what the U.S. is going after is a sole but its eternal goal -- pursuing the maximization of its own interests.

The Middle East and North Africa is of vital importance to Washington.

In a political and security sense, after the world-shaking 9/11 terror attacks, the U.S. launched two wars in Afghanistan and Iraq, in a bid to crush the al-Qaida terrorist network and its affiliates and foil any attempt to launch similar terror attacks on American soil.

Over the years, America has been trying hard to sell U.S. values and political systems to people in that region, in hopes of undermining anti-U.S. forces and bolstering new regimes there.

Economically, the Middle East and North Africa is America's crucial energy sources. The region's crude oil and natural gas reserves account for 60 percent and 45 percent of the world's total respectively. Currently, the U.S. imports more than 4 billion barrels of oil annually, of which 45 percent comes from the Middle East and North Africa.

Therefore, safeguarding America's oil interests in the region has always been a priority of its foreign policy. As former U.S. Federal Reserve Chairman Alan Greenspan has once put it, the U.S.-led war in Iraq was in a large extent related to oil.

Now, the U.S. is strongly urging Libyan leader Muammar Gaddafi to step down. People have every reason to doubt America's motives, as Libya has the largest oil reserves in Africa.

By promoting American-style values and political systems, Washington wants to seize the moral high ground. By the so-called democracy-building effort, it aims to gain the initiative and maintain and consolidate its vested interests there.

However, as it always does, the U.S. this time also has a double standard in advocating "democracy" in the region. To countries which are traditionally not on good terms with Washington, such as Iran and Libya, the U.S. is sharply lashing out at their governments; while to those who have maintained closer ties with it over the years, Washington is far less vocal.

A truth hard to ignore is that, the U.S. interference in other countries' domestic affairs under the excuse of democracy will only lead to turbulence in the region.

Iraq is a case in point. The U.S. launched the Iraq war in 2003 and toppled the regime of Saddam Hussein. But the country and the Iraqi people have suffered a lot since the outbreak of the war.

The turmoil in some Middle Eastern and North African countries has already had a negative impact on political stability and economic development in the region and the world at large.

History shows that any foreign interference based on self-interest, no matter how high-sounding the promises and declarations are, will in the final analysis do no good for stability in the region and other parts of the world.