Rudy Guiliani knows a thing or three about the impact of terrorist attacks on a city – and a country.

The former New York mayor was on duty when the planes crashed into the World Trade Center on 9/11, launching the United States into a ground war in Afghanistan and, later, Iraq.

Appearing on MSNBC the other day in the wake of the Boston Marathon bombing, Guiliani told commentator Chris Matthews that it’s important to keep this single attack in some perspective. He agreed with Boston officials’ decision to lock the city down for several hours while the bombing suspects were still at large. He then said that the nation needs to understand something about the relative safety it has enjoyed since the 9/11 attacks.

His point essentially was that two presidential administrations, the Bush administration and now the Obama administration, “have done a very good job” of heading off further terror attacks since that horrible September day in 2001.

The former mayor noted also that law enforcement agencies have been quite successful in catching terror suspects before they have done their evil deeds, with most of that detection occurring under the public radar. We’ll never know precisely how many plots have been foiled, Guiliani suggested.

As horrifying as the Boston bombing was and the horror it provoked in a great American city, this isn’t the time to panic and fear that the nation is under attack once again. The authorities in Boston did their job. Order is being restored daily.

Let’s always be alert, but let’s also get on with our lives.