Many Floridians were surprised and deeply shaken by the arrest earlier this month of a naturalized American citizen from Kosovo who is accused of plotting to attack various sites in Tampa in violent retaliation for America's "war against Islam."

Sami Osmakac's arrest in a Federal Bureau of Investigation sting is part of a sadly familiar post-9/11 narrative.

It is the tale of an American citizen and resident who became infected with the same ideologies of extreme intolerance that motivated the 9/11 terrorists, and who was very much intent on carrying out an attack on U.S. soil.

Investigators say Osmakac discussed with an informant his desire to carry out a terrorism spree in the Tampa area, mentioning bridges, nightclubs and a sheriff's office as possible targets. They say he claimed that he originally wanted to target the military but decided against it, concluding that "their bases are so locked up, I have to do something else."

He was arrested after taking possession of what he believed to be explosives and weapons from an undercover agent.

Osmakac's anti-Western and extremist beliefs were no secret. In a video posted on YouTube in March 2011, he openly charged that the West was involved in a war against Islam and proclaimed this war a "holy war" for Muslims.

Investigators say he also recorded a video in preparation for his imminent attack on the evening of his arrest. Although full details of the video have not been released, court documents indicate that he "stated his belief that Muslims' 'blood' was more valuable than that" of non-Muslims and "that he wanted 'pay back' for wrongs he felt were done to Muslims."

Osmakac appears to have been self-radicalized, although Kosovar officials stated that he had met with Muslim extremists during visits to his native land.

This dramatic arrest should serve as a powerful reminder that, despite the strides we have made in America to enhance security, bolster the presence of law enforcement at airports and rail stations, and ensure that our major metropolitan areas are protected from terror threats, the threat of Islamic extremism is still among the most serious and potent dangers to the safety and security of the United States.

And it is a threat that needs to be carefully watched, one that we must be constantly on alert for in every corner of our nation as well as on the World Wide Web, which is increasingly becoming a second front in the war on terror, and as well as a gathering place for would-be jihadists.

Violence in the name of Islam is a menace that penetrates our borders invisibly — mainly through the Internet, where jihadists post and distribute English-language anti-West recruitment propaganda specifically designed to radicalize American audiences. American citizens have with alarming regularity been influenced by online materials that justify and sanction violence.

In just the past three years, terror plots similar to that hatched by Osmakac have been uncovered and — thankfully — prevented, in New York, Washington State, Texas, Illinois, Washington, D.C., Maryland and Oregon. Two deadly attacks against military personnel in 2009, at the Fort Hood military base and at a military recruiting station in Arkansas, demonstrated the particular danger posed by extremists who — though unaffiliated with Islamic terrorist groups — share their ideological goals.

Anti-Semitism has also played a significant role in the radicalization process of many of these same extremists.

In one of Osmakac's online videos, he stated that Jews corrupted their religion by changing the Torah and that Jews wanted to kill Jesus because he was a Muslim prophet who was sent to correct this corruption. In other videos, he compared Jews to animals and the devil, and said that God has cursed them.

Relationship-building with law enforcement and with the Muslim community is critical to combating the threat of homegrown Muslim extremists influenced by violent ideologies developed by al-Qaida and other foreign terrorist organizations that promote hatred of Jews and America.

It is also important to recognize that there is a distinction between legitimate concerns about Islamic extremism and unacceptable stereotyping. We must not only expose the threat of Islamic extremism but also work to ensure Muslim-Americans feel that they are accepted as full Americans. This is not "political correctness" but the American way.