On Oct. 12, 2000, eight years ago this past Sunday, agents of al Qaeda attacked the USS Cole in the Port of Aden killing 17 American sailors. The Navy transported the damaged Cole to Northrop Grumman shipyards at Pascagoula for fourteen months of repair. The Cole was in port at Pascagoula during the 9/11 attacks of 2001.

Thinking about the Cole reminded me of other pre-9/11 al Qaeda terrorist attacks. In 1993, Ramzi Yousef masterminded the bombing of the World Trade Center (which would be totally destroyed by his uncle Khalid Sheikh Mohammed's attack nine years later). In 1998, al Qaeda struck American embassies in Narobi, Kenya and Dar es Salaam, Tanzania: killing hundreds including Americans. Then the Cole. Then 9/11. We live in a dangerous world and America faces enemies foreign and domestic.

I visited the International Spy Museum in Washington DC in 2005 and went through a special exhibit titled "The Enemy Within: Terror in America - 1776 to Today." The exhibition featured domestic terrorism from turn of the century anarchists to the Ku Klux Klan to Purto Rican nationalists to the Weather Underground to radicals like Timothy McVeigh or The Unabomber.

The exhibit followed the FBI's definition of terrorism: "the unlawful use of force and violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives."

I was particularly drawn to the exhibit's focus on the Klan as it highlighted with pictures, videos and documents, the Imperial Wizard of the White Knights of the Ku Klux Klan, Sam Bowers of Laurel, Mississippi. Bowers was suspected in hundreds of bombings and attacks. He orchestrated the fire-bombing that killed Vernon Dahmer and masterminded the killings of Andrew Goodman, Michael Schwerner, and James Chaney in Neshoba County. Time Magazine called Bowers "the most dangerous man ever to don a white hood."

The exhibit featured separatist extremists like Timothy McVeigh who killed 168 Americans in his destruction of the Alfred P. Murrah Federal Building in Oklahoma City in 1995, eco-terrorists like the Earth Liberation Front (ELF), and Theodore Kaczynski, the Unabomber.

In a critical article on the exhibit, the Washington Post noted, "the exhibit quite correctly labels as terrorism the violence of the Weather Underground and other bomb-throwing radical student groups of the '60s and '70s, who justified their actions as means of opposing the war in Vietnam." The Weather Underground is described by the FBI as "a small, violent offshoot of the Students for a Democratic Society (SDS), created in the turbulent '60s to promote social change."

The Weather Underground claimed responsibility for dozens of attacks including bombings of the U.S. Capitol Building, the Pentagon, and the US State Department. In an article appearing in the New York Times on September 11, 2001, one of the organization's founders, Bill Ayers, said "I don't regret setting bombs" and looking back on their actions, "I feel we didn't do enough."

Ayers and his wife Bernadine Dohrn, another leader and founder of the Weather Underground, unrepentant of their past domestic terrorism, are now engaged in peaceful social radicalism in Chicago where they formed political alliances with Barack and Michelle Obama: launching an Obama political campaign in their home, supporting him with campaign funds, and serving and working together on the Chicago nonprofit Woods Fund, as well as the Chicago Annenberg Challenge. When Obama was a community organizer, it was folks like Ayers and Dohrn in his community.

Whether Obama's association with Ayers disqualifies him from being president is a question of such serious nature it deserves more than a dismissive denial from his campaign. Imagine if Obama were a Republican from Oklahoma with ties to McVeigh; or from Mississippi with ties to Bowers.

When former Klansman David Duke ran for Governor of Louisiana in 1991, there were bumper stickers supporting former Gov. Edwin Edwards' electoral comeback, "Vote for the Crook. It's Important." Obama's recent association with a former terrorist is important.

The President of the United States is Commander-in-Chief of more than two million men and women, active and reserve, who pledged to "support and defend the Constitution of the United States against all enemies, foreign and domestic." Bill Ayers was one of those domestic enemies who remains unrepentant of his past crimes. Obama's relationship with Ayers deserves a proper vetting by America's media watchdogs. Voters can determine whether there are credible criticisms.

The anniversary of the USS Cole attack reminds us we live in a serious world where foreign enemies of the United States seek to kill Americans. January will see the inauguration of the next President of the United States, and the thirty-fourth anniversary of the Weather Underground's bombing of the U.S. State Department in Washington DC. Which will Bill Ayers be celebrating the most?

Brian Perry of Jackson, a former congressional aide, is a partner in a public affairs firm. Reach him at reasonablyright@brianperry.ms.