The following is text of a speech delivered by Sen. Rand Paul (R-Ky.) at the Heritage Foundation on February 6, 2013.

Foreign policy is uniquely an arena where we should base decisions on the landscape of the world as it is . . . not as we wish it to be. I see the world as it is. I am a realist, not a neoconservative, nor an isolationist.

When candidate John McCain argued in 2007 that we should remain in Iraq for 100 years, I blanched and wondered what the unintended consequences of prolonged occupation would be. But McCain's call for a hundred year occupation does capture some truth: that the West is in for a long, irregular confrontation not with terrorism, which is simply a tactic, but with Radical Islam.

As many are quick to note, the war is not with Islam but with a radical element of Islam—the problem is that this element is no small minority but a vibrant, often mainstream, vocal and numerous minority. Whole countries, such as Saudi Arabia, adhere to at least certain radical concepts such as the death penalty for blasphemy, conversion, or apostasy. A survey in Britain after the subway bombings showed 20% of the Muslim population in Britain approved of the violence.

Some libertarians argue that western occupation fans the flames of radical Islam – I agree. But I don't agree that absent western occupation that radical Islam "goes quietly into that good night." I don't agree with FDR's VP Henry Wallace that the Soviets (or Radical Islam in today's case) can be discouraged by "the glad hand and the winning smile."

Americans need to understand that Islam has a long and perseverant memory. As Bernard Lewis writes, "despite an immense investment in the teaching and writing of history, the general level of historical knowledge in American society is abysmally low. The Muslim peoples, like everyone else in the world, are shaped by their history, but unlike some others, they are keenly aware of it."

Radical Islam is no fleeting fad but a relentless force. Though at times stateless, radical Islam is also supported by radicalized nations such as Iran. Though often militarily weak, radical Islam makes up for its lack of conventional armies with unlimited zeal.

For Americans to grasp the mindset of radical Islam we need to understand that they are still hopping mad about the massacre at Karbala several hundred years ago. Meanwhile, many Americans seem to be more concerned with who is winning Dancing with the Stars.

Over 50 percent of Americans still believe Iraq attacked us on 9/11. Until we understand the world around us, until we understand at least a modicum of what animates our enemies, we cannot defend ourselves and we cannot contain our enemies.

I think all of us have the duty to ask where are the Kennans of our generation? When foreign policy has become so monolithic, so lacking in debate that Republicans and Democrats routinely pass foreign policy statements without debate and without votes, where are the calls for moderation, the calls for restraint?

Anyone who questions the bipartisan consensus is immediately castigated, rebuked and their patriotism challenged. The most pressing question of the day, Iran developing nuclear weapons is allowed to have less debate in this country than it receives in Israel.

In Israel, the current head of the Mossad, Tamir Pardo, states that we need to quit discussing Iran and nuclear weapons as an "existential" threat to Israel as that confines us to only one possible cataclysmic response. The former head of the Mossad, Meir Dagan, also cautions of the unintended consequences of pre-emptive bombing of Iran, both the possibility the strikes are ineffective and that Israel suffers a significant conventional missile response.

Yuval Diskin, the former chief of Shin Bet, Israel's domestic security service, recently said "an attack against Iran might cause it to speed up its nuclear program."

Israel's army chief of staff suggested in an interview with the Israeli newspaper Haaretz that the Iranian nuclear threat was not quite as imminent as some have portrayed it.

On the other side of the coin, Prime Minister Netanyahu warns that Iran is on the verge of obtaining nuclear weapons.

It seems that debate over Iran is more robust in Israel than in the US.

I have voted for Iranian sanctions in the hope of preventing war and allowing for diplomacy. The sanctions have not been fully implemented but they do appear to have brought Iran back to the negotiating table.

I did, however, hold up further sanctions unless Sen. [Harry] Reid allows a vote on my amendment that states, "Nothing in this bill is to be interpreted as a declaration of war or a use of authorization of force." The debate over war is the most important debate that occurs in our country and should not be glossed over.

I am persuaded, though, that for sanctions to change Iran's behavior we must have the commitment of Iran's major trading partners, especially China, Russia, Japan, and India.

Understandably no one wants to imagine what happens if Iran develops a nuclear weapon. But if we don't have at least some of that discussion now, then the danger exists that war is the only remedy.

No one, myself included, wants to see a nuclear Iran. Iran does need to know that all options are on the table. But we should not pre-emptively announce that diplomacy or containment will never be an option.

In a recent Senate resolution, the bipartisan consensus stated that we will never contain Iran should they get a nuclear weapon. In the debate, I made the point that while I think it unwise to declare that we will contain a nuclear Iran, I think it equally unwise to say we will never contain a nuclear Iran. War should never be our only option.

Let me be clear: I don't want Iran to develop nuclear weapons but I also don't want to decide with certainty that war is the only option.

Containment, though, should be discussed as an option with regard to the more generalized threat from radical Islam. radical Islam, like communism, is an ideology with far reach and will require a firm and patient opposition.

In George Kennan's biography, John Gaddis describes President Clinton asking Strobe Talbot "why don't we have a concept as succinct as 'containment.'" Talbot's response [was]"that 'containment' had been a misleading oversimplification; strategy could not be made to fit a bumper sticker. The president laughed. . . "that's why Kennan's a great diplomat and scholar and not a politician."

Kennan chafed that his opponents drew conclusions from it that were disagreeable to him but the fact of the matter is that the concept of containment succinctly described a strategy or, as Gaddis put it, "a path between the appeasement that had failed to prevent WWII and the alternative of a third world war."

What the United States needs now is a policy that finds a middle path. A policy that is not rash or reckless. A foreign policy that is reluctant, restrained by Constitutional checks and balances but does not appease. A foreign policy that recognizes the danger of radical Islam but also the inherent weaknesses of radical Islam. A foreign policy that recognizes the danger of bombing countries on what they might someday do. A foreign policy that requires, as Kennan put it, "a long term, patient but firm and vigilant containment of . . . expansive tendencies." A policy that understands the "distinction between vital and peripheral interests."

No one believes that Kennan was an isolationist but Kennan did advise that non-interference in the internal affairs of another country was, after all, a long-standing principle of American diplomacy that should be excepted only when: A) " there is a sufficiently powerful national interest" and B) when "we have the means to conduct such intervention successfully and can afford the cost."

In Kennan's famous X article he argues that containment meant the "application of counter-force at a series of constantly shifting geographical and political points, corresponding to the shifts and manoeuvres of Soviet policy." He later clarified, though, that did not necessarily mean that the application of counter-force had to mean a military response. He argued that containment was not a strategy to counter "entirely by military means." "But containment was not diplomacy [alone] either."

Like communism, radical Islam is an ideology with worldwide reach. Containing radical Islam requires a worldwide strategy like containment. It requires counterforce at a series of constantly shifting worldwide points. But counterforce does not necessarily mean large-scale land wars with hundreds of thousands of troops nor does it always mean a military action at all.

Kennan objected to the Truman doctrine's "implied obligation to act wherever Soviet aggression or intimidation occurred, without regard to whether American interests were at state or the means existed with which to defend them." He was also concerned that the Truman doctrine was "a blank check to give economic and military aid to any area in the world."

Likewise, today's "Truman" caucus wants boots on the ground and weapons in the hands of freedom fighters everywhere, including Syrian rebels. Perhaps we might want to ask the opinion of the 1 million Syrian Christians, many of whom fled Iraq when our Shiite allies were installed. Perhaps, we might want to ask: Will the Syrian rebels respect the rights of Christians, women, and other ethnic minorities?

In the 1980s, the war caucus in Congress armed bin Laden and the mujaheddin in their fight with the Soviet Union. In fact, it was the official position of the State Department to support radical jihad against the Soviets. We all know how well that worked out.

Out of the Arab Spring new nations have emerged. While discussion of Iran dominates foreign affairs, I think more time should be allotted to whether we should continue to send aid and weapons to countries that are hostile to Israel and to the United States. I, for one, believe it is unwise to be sending more M1 tanks and F-16 fighters to Egypt.

Kennan argued that "integrating force with foreign policy did not mean 'blustering, threatening, waving clubs at people and telling them if they don't do this or that we are going to drop a bomb on them.'" But it did mean maintaining "a preponderance of strength."

Kennan wrote, "The strength of the Kremlin lies in the fact that it knows how to wait. But the strength of the Russian people lies in the fact that they know how to wait longer." Radical Islam's only real strength is just such an endless patience. They know we eventually will leave. They simply wait for us to leave and leave we eventually must. We cannot afford endless occupation but this does not mean that by leaving we cannot and will not still contain radical Islam.

Everybody now loves Ronald Reagan. Even President Obama tries to toady up and vainly try to resemble some Reaganism. Reagan's foreign policy was robust but also restrained. He pulled no punches in telling Mr. Gorbachev to "tear down that wall." He did not shy from labeling the Soviet Union an evil empire. But he also sat down with Gorbachev and negotiated meaningful reductions in nuclear weapons.

Many of today's neoconservatives want to wrap themselves up in Reagan's mantle but the truth is that Reagan used clear messages of communism's evil and clear exposition of America's strength to contain and ultimately transcend the Soviet Union.

The Cold War ended because the engine of capitalism defeated the engine of socialism. Reagan aided and abetted this end not by "liberation" of captive people but by a combination of don't mess with us language and diplomacy, not inconsistent with Kennan's approach.

Jack Matlock, one of Reagan's national security advisors, wrote, "Reagan's Soviet policy had more in common with Kennan's thinking than the policy of any of Reagan's predecessors."

Reagan himself wrote, "I have a foreign policy. I just don't happen to think it's wise to tell the world what your foreign policy is." Reagan's liberal critics would decry a lack of sophistication but others would understand a policy in having no stated policy, a policy of strategic ambiguity If you enumerate your policy, if you telegraph to the Soviets that the Strategic Defense Initiative is a ploy to get the Soviets to the bargaining table, the ploy is then made impotent.

Strategic ambiguity is still of value. The world knows we possess an enormous ability of nuclear retaliation. Over 60 years of not using our nuclear weapons shows wise restraint. But for our enemies to be uncertain what provocation may awaken an overwhelming response, nuclear or conventional, is an uncertainty that still helps to keep the peace.

I recognize that foreign policy is complicated. It is inherently less black and white to most people than domestic policy. I think there is room for a foreign policy that strikes a balance.

If for example, we imagine a foreign policy that is everything to everyone, that is everywhere all the time that would be one polar extreme.

Likewise if we imagine a foreign policy that is nowhere any of the time and is completely disengaged from the challenges and dangers to our security that really do exist in the world – well, that would be the other polar extreme.

There are times, such as existed in Afghanistan with the bin Laden terrorist camps, that do require intervention.

Maybe, we could be somewhere, some of the time and do so while respecting our Constitution and the legal powers of Congress and the Presidency.

Reagan's foreign policy was much closer to what I am advocating than what we have today. The former chairman of the American Conservative Union David Keene noted that Reagan's policy was much less interventionist than the presidents of both parties who came right before him and after him.

I'd argue that a more restrained foreign policy is the true conservative foreign policy, as it includes two basic tenets of true conservatism: respect for the Constitution and fiscal discipline.

I am convinced that what we need is a foreign policy that works within these two constraints, a foreign policy that works within the confines of the Constitution and the realities of our fiscal crisis. Today in Congress there is no such nuance, no such moderation of dollars or executive power.

Last year, I introduced a non-binding sense of the Senate resolution reiterating the president's words [from] when he was a candidate that no president should go to war unilaterally without the approval of Congress unless an imminent threat to our national security exists.

Not one Democrat voted to support candidate Obama's words and only 10 Republican senators voted to support the notion that congressional authority is needed to begin war.

Some well-meaning senators came up to me and said, Congress has the power of the purse strings and can simply cut off funds. The problem is that there is occasionally a will to avoid war in the beginning but rarely, if ever, is there the resolve to cut off funding once troops are in the field. No historic example exists of Congress cutting off funds to a war in progress. Even during Vietnam, arguably our most unpopular war, funds were never voted down.

Madison wrote, "The Constitution supposes what history demonstrates, that the Executive is the branch most prone to war and most interested in it, therefore the Constitution has with studied care vested that power in the Legislature."

Since the Korean War, Congress has ignored its responsibility to restrain the President. Congress has abdicated its role in declaring war.

What would a foreign policy look like that tried to strike a balance? First, it would have less soldiers stationed overseas and less bases. Instead of large, limitless land wars in multiple theaters, we would target our enemy and strike with lethal force.

We would not presume that we build nations nor would we presume that we have the resources to build nations. Many of the countries formed after WWI are collections of tribal regions that have never been governed by a central government and may, in fact, be ungovernable.

When we must intervene with force, we should attempt to intervene in cooperation with the host government.

Intervention against the will of another nation such as Afghanistan or Libya would require a declaration of war by Congress. Such constitutional obstacles purposefully make it more difficult to go to war. That was the Founders' intention: To make war less likely.

We did not declare war or authorize force to begin war with Libya. This is a dangerous precedent. In our foreign policy, Congress has become not even a rubber stamp but an irrelevancy. With Libya, the president sought permission from the UN… from NATO… from the Arab League—everyone but the US Congress! And how did Congress react? Congress let him get away with it.

The looming debt crisis will force us to reassess our role in the world.

Admiral Mullen calls the debt the greatest threat to our national security. Former Defense Secretary Robert Gates noted that "at some point fiscal insolvency at home translates into strategic insolvency abroad." Gates added that addressing our financial crisis will require both "re-examining missions and capabilities" and perhaps most importantly, "will entail going places that have been avoided by politicians in the past."

It is time for all Americans, and especially conservatives, to become as critical and reflective when examining foreign policy as we are with domestic policy. Should our military be defending this nation or constantly building other nations? What constitutes our actual "national defense" and what parts of our foreign policy are more like an irrational offense? It is the soldier's job to do his duty—but it is the citizen's job to question their government—particularly when it comes to putting our soldiers in harm's way.

And of course, the question we are forced to ask today is, Can we afford this?

I hope such questions begin to be asked and we see some sort of return to a constitutional foreign policy. I hope this occurs before the debt crisis occurs and not amidst a crisis. To that end, I will fight to have a voice for those who wish who wish to see a saner, more-balanced approach to foreign policy.

Rand Paul is a U.S. senator from Kentucky.