Since 9/11, 21 people have been killed in this country at the hands of jihadist terrorists, including the four who tragically lost their lives in the Boston bombing this April and the 13 killed at Fort Hood in 2009 by U.S. Army Major Nidal Malik Hassan. During the same period, 23 people were murdered by protagonists of the domestic radical right, including the six who were slaughtered last August at a Sikh temple near Milwaukee, Wis., by neo-Nazi Wade Michael Page.

In the case of the Sikh temple killings, it seems safe to assume that Page was motivated by anti-Muslim hatred but did not understand that turbaned Sikhs have nothing to do with Islam. That was only the latest attack aimed at Muslims that resulted in Sikh deaths since 9/11. The first came just four days after the Al Qaeda attacks with the murder of Balbir Singh Sodhi, slain outside his Arizona gas station by a man who had promised to “go out and shoot some towel-heads.”

Now, the same kind of hatred that motivated Page and Arizona killer Frank Roque is bubbling to the surface again in the wake of the Boston bombings.

By the time the Boston suspects were identified as Muslim immigrants, the U.S. Muslim community already was cowering. Already, there had been reports of a man in New York and a woman near Boston attacked by hate criminals. The Council on American-Islamic Relations (CAIR) hurriedly called a news conference with four other Muslim organizations to condemn all terrorism — and to advise Muslims and Islamic institutions in America to beef up security procedures.

Then the hate really began to fly.

Bryan Fischer of the American Family Association said anyone who believes the Koran is “the holy book of God” should be banned from immigrating. The Eagle Forum’s Phyllis Schlafly called for bringing back the infamous House Committee on Un-American Activities to probe “jihadists” and “fellow travelers.” Pam Geller’s American Freedom Defense Initiative called for Muslim profiling, surveillance of mosques and a halt to all Muslim immigration. Right-wing author Ann Coulter said the wife of one bombing suspect “ought to be in prison for wearing a hijab.”

Larry Klayman of Judicial Watch declared his outrage that an accidental blast at a Texas fertilizer plant and the sending of ricin-laced letters were not being investigated for possible Muslim terrorist connections. Former Fox News celebrity host Glenn Beck claimed that a Saudi student cleared early on in the investigation was actually an “armed and dangerous” “control agent” being protected by the Obama administration. And televangelist Pat Robertson, who has blamed hurricanes on gay people, pointedly mocked the “religion of peace.”

There is no question that the threat of homegrown jihadist attacks is real. We wrote about that rising phenomenon in our Summer 2011 issue, which explored the shift from external to internal jihadist threats. But there also is no question that the American Muslim community is, by and large, a peaceful one that abhors terrorism in all its forms and that cooperates with law enforcement in exemplary ways.

A recent study by noted terrorism expert Peter Bergen and the New America Foundation found that Muslims and non-Muslims were “just as likely” to cooperate with authorities by tipping them off to plots, and it specifically rejected New York Republican Congressman Peter King’s 2011 claim that most Muslims won’t help police. Another study, issued by the Triangle Center on Terrorism and Homeland Security in 2011, reported that 48 of 120 Muslims suspected of plotting terror attacks in the U.S. since 9/11 were turned in by fellow Muslims.

Bergen’s study also found that while every death is a tragedy, “Islamist terrorism has been less deadly in the United States than other forms of terrorism since September 11.” But that hasn’t dampened anti-Muslim feeling.

Muslims in this country have been here before. Right after the 9/11 Al Qaeda attacks, anti-Muslim hate crimes exploded by some 1,600%, to the surprise of very few people. But that crime wave fell back right away, dropping by about two thirds in 2002, in large part because of President George W. Bush’s repeated speeches to the effect that the culprit was Al Qaeda, not Islam. Then, however, after seven more years of overall decline, anti-Muslim hate crimes shot up again by 50%.

That 2010 jump, along with similar numbers in 2011, is best explained by the rancor stirred up by the Muslim-bashing propaganda that characterized those two years — Geller’s crusade against New York’s “Ground Zero Mosque,” fights over mosques in other states, attacks on Shariah Islamic law, and the rhetoric surrounding King’s 2011 congressional hearing on the radicalization of U.S. Muslims.

At press time, President Obama had not yet spoken out against the wave of intolerance against Muslims that clearly was building. He should. As President Bush showed in 2001, good leadership at the right moment can make us a better nation.