For Frank Gaffney, President of the Center for Security Policy, the federal government should be thinking bigger -- for example, our entire electric grid.
"Unfortunately, there's a lot to evidence that enemies of this country have figured out that if you attack that very vulnerable grid, they could cause cataclysmic damage to the American people," says Gaffney.
Gaffney also says the domino effect of an attack on the electric grid could not only reach all corners of the nation, but it could be deadly.
"Water requires power, food requires power, transportation requires electricity, finance, telecommunications," Gaffney adds.
With millions of people using public transportation every day in this country's big cities, experts warn underground tunnels and trains may be another potential threat.
"Right now ISIS's primary means of attack against the west is almost certainly an urban warfare style of attack," says Daveed Gartenstein-Ross of the Foundation for Defending Democracies.
Ross says ISIS is still very limited in its capability, especially when compared to the terrorist attacks of 9-11.
"Isis does not have the same capabilities that al Qaeda did back then. Plus, we've really hardened our defenses which makes carrying out a spectacular attack more difficult . We should be vigilant, we don't need to be afraid," adds Ross.
At least -- he says -- not yet.