There is one fundamental element that is absolutely necessary for an isolationist foreign policy. Isolation. Isolationism without physical isolation is as much good as belligerence without an army to back it up.
As far back as 1897 and long before any American involvement in Europe, Operational Plan Three called for shelling New York and seizing parts of Virginia, as a staging base for attacks on Washington and Baltimore. Plans were drawn up in Germany for the occupation of Boston and Philadelphia.
Vice-Admiral August Thomsen wrote, "At the moment every thinking German officer is occupied with the consequences of a belligerent conflict between Germany and the United States of America."
No American politician was thinking the same thing. America had not intervened in any European wars and had no interest in Germany. But that didn't matter. The Kasier wanted to seize parts of the hemisphere and that meant breaking the dominant power in the region. America's weak fleet made it seem like an easy target.
That is the most important part of the equation that isolationists fail to include in their calculations. Regardless of our foreign policy, we are still a target. Whatever our calculations are, potential enemies may have calculations entirely different from our own. They don't just react to what we do, they have their own plans and agendas. Passivity isn't a defense for the ostrich or for a nation.
In 1900 while America slept, German diplomats were scouting Cape Cod and Provincetown as support bases for an attack on Boston. And the Germans weren't alone. In the early 20th century there were British plans for an assault on New England. But Germany's failure to formulate an alliance with other European powers against the United States led to the abandonment of Operational Plan Three.
When Charles Lindbergh ridiculed the idea of a foreign attack on America, such an attack was less than a year away, but variations of it had been planned by European powers for a good deal longer than that. Terrorist attacks by foreign agents were a now forgotten reality during WW1, including the Black Tom explosion which severely damaged the Statue of Liberty, the Vanceboro bridge bombing, and in an early form of biological warfare a laboratory in Chevy Chase was working on anthrax and glanders cultures to be used on horses.
With the jet plane and the intercontinental ballistic missile, isolationism became completely unworkable without strong deterrence. Even if the United States had chosen to abandon Europe, it would still have needed massive nuclear missile stockpiles, a sizable fleet and military, and a policy of Mutually Assured Destruction just to pursue a policy of isolationism. And had the USSR managed to make even deeper inroads in South America, the United States would have been forced to either push it out or increase the size of its forces to compensate for the loss of a buffer zone against preemptive attacks.
It's not impossible to have an isolationist foreign policy today, to cut any alliances with the rest of the world. But there's a fundamental difference between a responsible and an irresponsible isolationist policy. A responsible isolationist policy recognizes that we have enemies who will act regardless of what we do and prepares against the possibility of war without actively seeking it out.
An irresponsible isolationist foreign policy however acts as if we have no enemies and that any talk that we have enemies is a conspiracy to bring us into a war. It accepts every bit of enemy propaganda as gospel and assumes that if we just "stop bothering them", they'll "stop bothering us". It assumes that the enemy is entirely motivated by our actions, that any conflict we are in is the result of our foreign policy and that isolationism will avert any such conflicts.
This is the version of isolationism that you hear in the Republican debates from Ron Paul. It's the version that Americans heard back in the 1930's from Lindbergh. Rather than recognizing that a military buildup is an important deterrent to war, it attacks military buildups as provocative. It assumes that the only possible reason why we might be attacked are foreign entanglements and if we just tuck our heads in then there will be no conflict.
American foreign policy can't turn back the clock on that history. It can affect events in the present day, but it can't undo the roots of a conflict that it has inherited. American foreign policy had a good deal to do with the rise of Islamic states built on petrodollars, but isolationism is certainly not going to make them go away. Certainly not Ron Paul's brand of isolationism which pretends that there is nothing wrong with Islam that can't be fixed with an American isolationist foreign policy.
During the last debate, Ron Paul asked why they're bombing us and not Sweden or Switzerland. The answer is very simple. You only bomb people who resist. Stockholm is 20 percent Muslim. Muslim terrorists operate out of Sweden, including a top Al-Qaeda leader, but they don't need to attack a territory that they're already on the way to ruling through natural demographics.
44 percent of Europe's population is over 45. Under 34 percent is under 30. Meanwhile half of European Muslims are under 30. The math isn't very hard to do. The only countries that need to be targeted by Muslim terrorists are those which have a high enough birth rate that demographics alone won't do the trick.
The First World country with the highest birth rate is Israel. It's also the country most targeted by Muslim terrorists. The First World country with the second highest birth rate is the United States. It is the country second most targeted by terrorists. The next major countries on the list are France and the UK. There's a term for this sort of thing. It's demographic suppression and political intimidation.
Back in the 19th century the Kasier hoped that shelling Manhattan and seizing a few cities would bring the United States to the negotiating table. Japan thought that bombing Pearl Harbor would accomplish the same thing. But while Tojo was wrong, the House of Saud was correct. September 11 brought the United States to the negotiating table with Islam. Muslims have been granted special privileges and their immigration rate has increased. That's one path to an eventual demographic domination.
Islamic attacks against the United States may emerge from various micro-events, but the macro-event from which they originate is the shared history of the Western world and the ongoing conflict between the Muslim world and the West. Some isolationists may act as if the United States can break with European history through assertion alone. It cannot. Like it or not it shares a common history and a common culture. America derives from Europe, and whether Americans recognize it or not, the rest of the world does. To Islam, America is not an island, it is another outpost of an enemy civilization that must be subdued so that the way of Mohammed will triumph around the world.
Ron Paul type isolationists fail to distinguish between the proximate causes of war and the ultimate causes of war. A proximate cause of war may be a ship that has wandered into the wrong area which may have been caused by a trade dispute which may have been caused by debts which may have been caused by growing militarism and greed for land. But none of those are truly the ultimate cause of war. The ultimate cause of war is the incompatibility of two systems and two civilizations within the same space.
Rationalism isolationism accepts that war may be inevitable but chooses to meet it on our terms. Irrational isolationism, which often carries with it defeatist and treasonous overtones, accepts the enemy's justifications for the conflicts and assumes that if we modify our behavior accordingly that there will be no need for war.
"Si vis pacem, para bellum," was a rule that the old Romans knew. If you would have peace, prepare for war. The emblem of the Strategic Air Command was an olive branch and thunderbolt held in a mailed fist. Its motto was "Peace is Our Profession". The SAC kept the peace through the threat of war. Only an isolationism that understands the meaning of that motto can be successful.