Fifteen years ago today, Timothy McVeigh detonated a truck filled with explosives in front of the Alfred P. Murrah Federal Building in downtown Oklahoma City, the deadliest domestic terrorist attack in U.S. history.
But how much safer are we now?
In the fifteen years since the Oklahoma City bombing, reports CBS News homeland security correspondent Bob Orr, we've seen other attacks by domestic extremists: The shootings at Fort Hood last fall, and the deliberate crash in February of a small plane into an IRS building in Texas are two examples.
But such domestic incidents have been overshadowed by the threat from al Qaeda.
Now with homegrown radicalism on the rise, some security experts warn we need to better secure the home front.
For the survivors of the Oklahoma City bombing, even 15 years later the wounds are still fresh.
"It seems like some weeks I cry every day, and sometimes you can go for a month and not cry," said bombing survivor Beverly Rankin.
That day, April 19, 1995, changed everything for the families of the 168 killed and the 600+ survivors.
And it changed the way all us live. Blast barriers now surround many office and federal buildings; heavily armed security forces routinely patrol train stations and airports.
Still, experts warn we remain vulnerable.
"Timothy McVeigh drove a truck up to the Murrah Building in Oklahoma City and detonated that bomb which was made of homemade components and ammonium nitrate; you could still do that tomorrow," security & terrorism expert Neil Livingstone told CBS News.
A CBS News poll found that nearly 40 percent of Americans now believe domestic terrorism is a bigger threat than international terrorism, a marked increase from the foreign-focused fears triggered by 9/11.
The militia movement is once again energized, fueled by critics who are angry with the government.
Bill Clinton, president at the time of the Oklahoma City attack, said today's rhetoric reminds him of 1995.
"I realized that there were a lot of parallels between the early '90s and now, both in the feeling of economic dislocation, and the level of uncertainty people felt," he told ABC.
Survivors and family members of those who died in the bombing are gathering at the blast site this morning to commemorate the anniversary, and to make a larger point - that we must remain vigilant.
Orr said the threat from domestic terrorism today is about the same as from transnational terror groups, but Orr said the big problem is the "lone wolf" - a radicalized American who can travel freely and reach across and touch real al Qaeda groups.
Orr said Najibullah Zazi, the man charged with plotting to bomb new York City's subway, is the poster boy for such a threat.
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