The backlash has already begun.
After an officer of Arab descent opened fire on fellow soldiers at Fort Hood, a leader of a conservative Christian group called for a ban on Muslims in the military.
"As soon as Muslims give us a foolproof way to identify their jihadis from their moderates, we'll go back to allowing them to serve,'' said Bryan Fischer of the American Family Association. "Until that day comes, we simply cannot afford the risk.''
It was the kind of reaction feared by Gen. George Casey, the Army chief of staff, who had called the shootings a "kick in the gut'' and warned they could "heighten the backlash'' against Muslim soldiers.
Whether last week's rampage, which left 13 soldiers dead, was religiously motivated is unknown. Maj. Nidal Malik Hasan has not talked to authorities, who are investigating his reported anger over the U.S.-led wars in Iraq and Afghanistan and his e-mail contacts with a radical Muslim cleric in Yemen.
Yet history shows that Muslims have served with honor not only in the U.S. Army but also in the militaries of other largely non-Muslim countries.
If any nation has reason to be wary about Muslims in its military, it is Israel. The Jewish state has fought several wars against Muslim countries and organizations, including Hamas in the Gaza Strip last winter.
But thousands of Muslims serve in the Israel Defense Forces, including an entire battalion, about 800 soldiers, of Bedouins.
A once-nomadic Arab people, the Bedouins are considered trustworthy enough to guard Israel's secretive nuclear facility at Dimona. In some poor Bedouin villages, most men voluntarily join the military even though they, like all Arabs, have long been exempt from the three years of service required of Jews and other Israeli citizens.
The reason for the exemption is less because of religion than because many Arabs support the Palestinians' quest for a state of their own.
"Due to the potential conflict between their national identities and their status as Israelis, we don't make it compulsory for (Arab) Muslims to join the IDF,'' Col. Ahmed Ramiz, the officer in charge of minorities, told the BBC.
As a result, the number of non-Bedouin Arabs in the army is negligible even though they make up nearly a fifth of Israel's 6 million people.
Among the citizens required to serve are the Druze, a Muslim sect in northern Israel.
Several Druze officers have reached the rank of general, including Imad Fares, praised for his command of soldiers along the Lebanese front. He resigned in August after lying about his wife's involvement in a minor accident while she was driving a military vehicle.
A prominent rabbi said the incident showed Druze were untrustworthy and should be banned from the military. But Israel's chief rabbi quickly came to their defense.
Many Druze have died "heroically for the land of Israel,'' Rabbi Yona Metzger said.
(Embarrassingly, a Jewish general was recently caught lying about a similar incident but is still on the job. The Druze say this shows "racial discrimination'' within the army.)
For Britain, Muslims have been fixtures in the military since its colonial days on the Indian subcontinent.
During World War II, "vast numbers of battalions came from what we would call the empire and they fought alongside us and the Americans with great bravery,'' says David Livingstone, a former Royal Navy commander and now a fellow at London's Royal Institute for International Affairs. "It was not an issue of religion, but of fighting against oppression.''
Thousands of Muslims who joined the army later settled in Britain, whose non-Anglo Saxon population has soared in recent decades. That prompted a push by Britain's highest ranking Muslim officer, Pakistani-born Rear Adm. Amjad Hussain, to recruit more ethnic minorities.
"I feel a lot of pride to be a part of an organization that is more interested in what you do rather than where you're from," Hussain said on his promotion in 2006.
But there are still only a few hundred Muslims in a total force of over 200,000. And the conflicts in Iraq and Afghanistan, which many British Muslims view as a war against Islam, have done little to boost enlistment.
As in Israel and Britain, Muslims in the United States make up a tiny percentage of the 1.4-million-strong armed forces — about 3,500 officially, with about half of those African-American converts to Islam. One of the highest ranking Muslim officers, a colonel, is a former Episcopalian who converted in college so he could marry an Egyptian.
Islamic organizations say the true number of Muslim service members could be as high as 12,000 because personnel don't have to list religious preference; Hasan, the Fort Hood suspect, did not.
The dearth of Arabic-speaking Muslims has been sorely felt since the Sept. 11 attacks and the invasion of Afghanistan. Before U.S. troops moved into Iraq in 2003, the General Accounting Office warned that the Army was so short of interpreters that it did not have "the linguistic capacity'' to support two major wars.
Since then, the Pentagon has tried to recruit more Muslims, especially those fluent in Arabic, and make military life more attractive to them. West Point dedicated its first mosque in 2006; combat troops can request halal meals that meet Islamic dietary requirements.
But the armed forces appear to have limited appeal for many of America's 5.8 million Muslims.
"Obviously this kind of incident" — the Fort Hood shooting — "is not going to be helpful in terms of recruiting for the military,'' says Ibrahim Hooper, spokesman for the Council on American-Islamic Relations. "But we have an all-volunteer military and if people wish to join, they will. If they're philosophically opposed, they won't.''
Times researcher Carolyn Edds contributed to this report. Susan Taylor Martin can be contacted at firstname.lastname@example.org.