With its nuclear industry, Detroit is considered a potential terror target
The Bush administration calls the US homeland the second front in its war with Iraq.
So I went to the border city of Detroit to find out how the authorities are protecting America from possible terrorist attacks.
Halal meat, Syrian cheese and Lebanese pickled grape leaves may not come as standard fare in many US supermarkets but in the Dearborn suburb of Detroit, home to the largest Arab-American community in the US, these products sit side-by-side with Coca-Cola, Hershey bars and Dorito crisps.
The 400,000 Arab-Americans in the city have been the focus of close attention by law enforcement officials since the 11 September 2001 attacks on New York and Washington.
The country's first terrorism-related trial is currently taking place in Detroit.
A person who is a threat to national security or a threat to the fabric of this nation I don't think will come out and say his true intentions
But since military action was launched against Baghdad, Iraqi-Americans in the community have been the focus of particular scrutiny.
Hundreds of Iraqis across the US have been questioned by the Federal Bureau of Investigation in case any agents or surrogates of Saddam Hussein's regime are willing to carry out terrorist attacks.
Many have been unnerved by the interviewing process, their deep suspicion of any police force based on the modus operandi of Iraqi police units.
Lawyer Nabih Ayad has represented five families who have been questioned.
Border security between the US and Canada has been stepped up
Over a cup of coffee at a Lebanese restaurant in Dearborn, he says that, as well as creating fear, the interrogations are unlikely to be of much use.
"A person who is a threat to national security or a threat to the fabric of this nation I don't think will come out and say his true intentions," he tells me.
Detroit's homeland security challenges range from its citizens to its geography.
Located on the border between the US and Canada, the city has a bridge and tunnel linking the two countries, supplies the region's drinking water and has a nuclear power plant down the road.
It is perhaps little wonder, then, that Detroit was the first city in the US to appoint a director for homeland security.
Sitting in his office in the fire department, Shelby Slater says the city's links with Canada and the location of major international companies in Detroit - Ford, GM and DaimlerChrysler all have their headquarters here - make the city a potential terrorist target.
US national security remains on alert
He says that with the country currently at war and the national alert status at yellow, residents "have to be on watch for suspicious package, suspicious vehicles".
"We also suggest they prepare a family disaster plan and a disaster kit," he adds.
Much attention is being paid to the Ambassador Bridge, the most important commercial link between the US and Canada.
When it was completed in 1929 it was the longest suspension bridge in the world, its span over the Detroit River expanding for more than 1,837 feet (560 metres).
Today it carries billions of dollars of trade between the two countries and has seen its security stepped up.
Kevin Weeks, the US official in charge of securing the bridge, says that "additional officers have been hired and fortunately we've received technology to assist us in screening the cars and the trucks as they enter the US."
Canadian Randy Burry has been driving his lorry across the Bridge for more than eight years, transporting "anything that needs carrying".
He says that over the past 19 months security has improved, with closer attention being paid to paperwork and thermo-scanning machinery being introduced.
But since the conflict with Iraq started, Randy says he has not noticed any discernible changes.
"The night before they went to war, I crossed over and it only took me half an hour," he says.
"I talked to guys after and they said there was no change the day the war started."
The US-Canadian border in nearly 5,592 miles (9,000 km) long.
In some parts, you take one golf shot in Canada and take the next one in the US.
That means the border is virtually impossible to make totally safe, but while border officials in Detroit admit it is not foolproof, they believe the new measures have made the US more secure.