At 17 years of age, Dzhennet Abdurakhmanova was widow -- a black widow.

During the March 29 rush hour, at Moscow's Lubjanka station, she detonated her bomb vest. Forty-five minutes later, a second "black widow" did the same at another subway station. Dozens died; scores more were injured.

Officials believe Dzhennet's attack was revenge for her husband's death. An Islamist separatist, Umalat Magomedov died fighting the Russians.

The black widows' bombs reverberated here in the United States. New York immediately beefed up its subway security. Sen. Joe Lieberman, I-Conn., warned all Americans to be extra-vigilant on buses and trains. "These are targets, and we know that," he declared.

Both responses were pretty stupid. Yes, separatist movements in Russia espouse Islamist dogma. But the United States and Russia have little common cause in the long war on terror. Their terrorists are not coming here -- at least not anytime soon.

American intelligence needs to prioritize and focus on our most dangerous enemies -- and they ain't in Chechnya. Here's a short list of the groups posing the most immediate threat to U.S. security.

Topping the list is al Qaeda in the Arabian Peninsula, the group behind the attempted Christmas bombing in Detroit. This outfit is largely based in Yemen.

Some intelligence operatives suspect al Qaeda would like to build up a stronger presence in Yemen, both for operational attacks on Western targets and as an alternative base if Pakistan has to be abandoned.

No. 2 on the list is Al-Shabaab, based on the other side of the Red Sea from Yemen. Government intelligence officials have found unambiguous links between al Qaeda and this Somali group, which has been actively recruiting among the Somali Diaspora in the U.S. Last year, one of those recruits took part in the suicide bombing of an African Union peacekeeping base in Mogadishu.

Coming in at No. 3 is Lashkar-e-Tayyiba (LeT). LeT carried out the horrific shootings in Mumbai, India, in 2008. It has evolved from being a terrorist group active primarily in Kashmir's separatist movement into a transnational force with a pan-Islamist agenda.

LeT started out in the 1990s, focusing its attacks against Indian security forces. Today it boasts a wide international network and spreads its attacks broadly, including civilian targets such as the hotel guests in Mumbai.

The group has made some very bad friends along the way. In addition to al Qaeda, one of LeT's most notorious allies is the shadowy D-Company, a global criminal syndicate run by Dawood Ibrahim. An underworld figure with established connections to both criminal and terrorist groups, Ibrahim has a flourishing franchise in Pakistan.

Nos. 4 and 5 on the list are Hamas and Hezbollah. Both are heavily backed by Iran. Both have global reach, including networks throughout Latin America that offer a backdoor into the United States.

As the world's No. 1 state sponsor of terrorism, Iran routinely uses terrorism as an instrument of foreign policy. Tehran's mullahs believe in the old adage "The enemy of my enemy is my friend."

Last month, Tehran released one of bin Laden's daughters from house arrest. There are other reports that Iran is aiding al Qaeda and the Taliban in Afghanistan. At some point, Iran may well order Hamas and Hezbollah to take on the U.S.

None of these enemies is 10 feet tall. All of them can be beaten. But all will become more dangerous if we ignore them. Or if we allow our security assets to be distracted and diffused by vaporous threats to the homeland, such as the black widows.