In the space of less than one week, two Canadian citizens described as Muslim coverts attacked sources of government authority. In two separate attacks, radicalized Muslim men using low-tech weaponry claimed the lives of two Canadian soldiers.

Sensitivity to the threat posed by homegrown radical Islam is a familiar condition across the Western world.

In late August, the United Kingdom urgently raised the terrorism threat level as the West prepared to go to war against the Islamic State in Iraq and Syria. The threat, Prime Minister David Cameron explained in a televised speech to British citizens, that the threat to U.K. security came not only from abroad but from radicalized citizens as well.

“Now people are rightly concerned about so-called foreign fighters who’ve travelled from Britain to Syria and Iraq, taken part in terrorist acts and now come back to threaten our security here at home and the scale of this threat is growing,” Cameron waned.

“We are stopping suspects from traveling by seizing passports, we’re barring foreign nationals from reentering the U.K., we’re depriving people of citizenship and we are legislating so we can prosecute people for all terrorist activity even where that activity takes place overseas,” the British Prime Minister continued.

In an emotional speech to the Canadian parliament on Thursday, Canadian Prime Minister Stephen Harper, too, addressed the threat posed by homegrown radicalism. “We’re all aware and deeply troubled that both of this week’s terrorist attacks were carried out by Canadian citizens, by young men born and raised in this peaceful country,” he said.

These leaders in nations with political cultures far more attuned to the sensibilities of the politically correct than are American elected officials are making a stunning admission: Their countries can no longer abide by a laissez-faire which allows radicalization to fester in sequestered communities which refuse to assimilate into the larger society around them.

Some Canadian voices are beginning to call for a broader conversation about homegrown terrorism. The Globe and Mail called the attacks on parliament a “turning point” and the likely start of a conversation about the nature of domestic Islamic terrorism.

“Canada, it seems, is under siege from within,” The Toronto Sun’s Michele Mandel wrote. She noted that despite heightened terror warnings, despite the shock of a deadly attack on uniformed Canadian soldiers just days prior, the government could not prevent this horrific assault on parliament.

It proves the startling and terrifying truth we now must face — no matter how vigilant we may be, it will be incredibly difficult to protect ourselves from the radicals hidden among our own countrymen.

Now an innocent man’s blood stains the granite Cenotaph, spilled not by a foreign enemy, but by an enemy within.

The United States is slightly better positioned than other Western nations to tamp down the threat posed by homegrown radical Islamic extremism. America’s history of valuing and promoting assimilation, and facilitating Americanization via societal integration, has reduced – though not entirely alleviated – the domestic threat posed by homegrown Islamic radicals. Pew Research Center polling in 2007 and again in 2011 found the majority of Muslim-Americans do not feel alienated are generally not predisposed to view Islamic fundamentalism in a positive light. But, as is the case in Canada, it is those who are possessed of the convert’s zeal that likely present the most danger.

As CNN reported, three Denver schoolgirls reportedly attempted to join the Islamic State but were detained in Germany on their way to the porous southern Turkish border. They might have become more of the “handful” of Americans the FBI estimates are fighting alongside Islamist militias in the Middle East.

Washington would be advised to get as serious about homegrown radicalism as are Canadian and British authorities. American has been lucky to avoid a low-tech ISIS-inspired attack on the homeland via a radicalized citizen, but the government cannot rely on luck forever.