With the US economy widely seen as poised to fall off a fiscal cliff in a matter of weeks, it would be understandable if Americans would want to enter a period of semi-isolationism, at least until the outlook improves somewhat. It would be understandable as well if newly-reelected President Barack Obama would considering reducing America’s profile on the international stage.

It would be understandable, said former US Secretary of Homeland Security and Pennsylvania governor Tom Ridge — but it would be a mistake. “Among both Republicans and Democrats there are significant factions that say we need to concentrate on our own problems,” Ridge told attendees of the second International Conference on Homeland Security in Tel Aviv. “But it seems to me it would be in the US’s interest to be more engaged with the rest of the world, not less.”

An isolationist US would lose out on business opportunities that could help its economy, said Ridge. But more importantly, he said, the only way to ensure the US’s safety is to cooperate with allies in the fight against terror.

Ridge made the comments during a conference session in which he discussed how much the world has changed since 9/11 — the pivotal event that, among other things, created the homeland defense industry, which is worth tens of billions of dollars worldwide. From airline travel to increased police surveillance of individuals, the world’s democracies are in a seemingly endless battle against forces that seek to destroy the Western way of life.

It’s no longer just al-Qaeda that the US has to worry about, said Ridge. “The experience of global terrorism has increased,” Ridge said. “Of course Hezbollah and Iran are of great concern to us, and there are many other groups around the world that have embraced the jihadist mindset. There is the cyber form of terrorism, such as that performed by Russia and China. There is also a great deal of concern over nuclear weapons — from Iran’s weapons program, of course, but also from the possibility that a terror group could get hold of a ‘dirty bomb’ and use it for blackmail or other purposes.

“There is also the possibility of biological warfare, where an enemy engineers a biological weapon. But we also have to be ready for what nature throws at us that we don’t have a solution for,” he added.

The bottom line: “The world is a much more dangerous and complicated place than it was on 9/11. I believe that working together with our allies is the only way to beat these dangers.”

As far as Ridge is concerned, the best ally for the US to work with on security matters is Israel. Ridge, in Israel to attend the conference, was heading a 15-company mission organized by the US Chamber of Commerce. Ridge is the chairman of the organization’s National Security Task Force, and he sees increasing cooperation with Israel as a good idea for both countries.

“Both politically and economically, Israel is one of our most significant allies globally and our most important ally in the Middle East,” Ridge said in a statement before the event. “Ensuring an environment of shared information and integrated technologies that have defense and security capabilities is crucial to the economic cohesion between the United States and Israel and between companies that operate in both countries.”

Ridge reiterated his thoughts during the event. “I met with Prime Minister Benjamin Netanyahu last year and he suggested increasing cooperation between the US and Israel in the area of homeland security,” which turned out to be an excellent idea, he said, because of the many innovative technologies Israel has developed for homeland security — many of which were on display at the conference.

“Israel and the US have a similar mindset when it comes to security,” Ridge said. “Our enemies must know that we care more about being respected than about being liked,” and that has been Israel’s watchword since the day it was created.

“I see many other opportunities to expand trade with Israel as well, such as in the energy sector, given Israel’s recent discoveries of large stores of natural gas. Our motto at the Chamber of Commerce is ‘growing jobs together,’” said Ridge — and there was no country better to do that with than with Israel, one of America’s staunchest allies.