The problem with liberalism being "positive" (as opposed to being negative, and against things "conservatives" support) is that it has already been proven that the majority of things which are traditionally "liberal" are just thinly guised implimentations of Marxist ideals. Marxist ideals which have been repeatedly proven to fail in practice over the last century.
What we see in the media (and in your post) is a fundamental confusion of terms, which is part of the reason why you seem somewhat bemused at the fact that Bush and the conservatives are in opposition to Iran, while the liberals are not. While the Islamic leaders in Iran are conservative Muslims, conservative Islam has a fundamentally different perspective on government than American conservatives. In fact, the "conservatives" in Iran are more alike US Liberals than US Conservatives. Let me explain.
The Marxist ideals as perpetrated by liberals, like the so-called "conservative" stance you outline as belonging to the Islamic extremists, have the exact same perspective on government as the Islamist extremists! That is, both seek to convert the country's government and populace to a worldview (both political and personal) that is contrary to how the majority views the world. Both want to instigate widespread government control of all manners of a person's daily life, whether it's through a mosque in Iran, government healthcare, or overly-intrusive substance and material control.
Now, this is not to say that Western Liberalism (as you define it - it seems you're referring to American Liberalism, an entirely different beast) does not have many redeeming qualities, or that it is a perfect analogy for the governmental Islam in Iran. There are a great deal of good ideas within US Liberalism, they are simply overshadowed by a Marxist thought process.
Additionally, you've completely misdefined American conservativism. You're assuming that it is the backbone behind the "neocons" in power. Why do you think Bush's approval rating is so low? Certainly part of it has to do with the war, but I assure you that a sizeable portion of it is due to his domestic policy. It is far, far too liberal and overreaching for the majority of Americans, from border control, health care, public education, and a number of other topics.
Really, the entire spectrum of political definition in the United States is fairly fucked up. You'll find conservatives and liberals both, in many respects, ascribe to Marxist ideals and Jeffersonian ideals - ideals which are largely mutually exclusive. Once you get out of college, you will find that there are plenty of conservative athiests, and many Christian liberals.
However, for the most part, people simply don't bother to think through the various characteristics of their beliefs and assure that they are internally consistent. This is largely because people are willfully ignorant, and don't bother to read the actual accounts of history, instead believing what they read online or see on TV. This is why we've got people who believe in "traditional family values" yet support governmental expansionism or socialized medicine. It's why we've got people who try and restrict or redefine the 2nd Amendment while pushing the bounds of the 1st Amendment to the obscene (which is fine, as long as they're willing to take responsibility for their actions).
Your "fighting Marxists" are a joke. The reason there are so few of them is because the ideal failed. Marxism was fundamentally flawed as it did not take into account human nature. At all. It assumed there would not be totalitarian dictators - just ordinary people with a thirst for power, like Hillary Clinton or George Bush - who would see the vacuum of a leader and fill it. Need I remind you of the millions of people killed in genocide throughout the world in the name of Communism - people who's only crime, in many respects, was to disagree that the system of Communism works? You've got a completely dillusional and fantastical view of Communism, one that is not based on fact or history. Please rectify this.
Mark my words: come election time, more Democrats will be voted into office due to a large number of single-issue voters who have come to believe the war in Iraq is wrong and that we should pull out. I guarantee you we will see an ever-increasing amount of state control as a result.
(And for what it's worth, I lump Bush into this "more govenrment" Marxist camp, as most of the things he has done have indeed been inline with what Hitler has done, much of which was directly from the writings of Karl Marx. Expect to have the government to allow anothe disaster, through which it will gain even more power in the minds of the populace, allowing it to do whatever it so pleases. Keep in mind that both Bush and Kerry were and are a part of the The New American Century Project.)
As for Iran's "Liberals" regaining the upper hand? You're sadly mistaken. The time for any action in this regard was years ago, before the Iranian government started pushing the Liberals out of power. If you recall your history of WWII, we are currently at the rough parallel to a period of years after the establishment of both Imperialist Japan and Nazi Germany, when they were building up politically, economically, culturally for expansionist behavior.
The Iranian society, at this point, might be open to repair much as Germany and Japan were after World War II. But, being as Iran's official government has stated on multiple occasions that it desires and seeks after a war - a full-on collision of civilizations, cultures, and militaries - with the West, there is no practical alternative. We can either wait for them to make the first overt attack against America - likely nuclear, as they haven't got much else - or we can go in and take care of their government now. I see no other option to the scenario they have pressed upon.
Oh, and you want to talk about bigoted, walk into any public university course on Marxism, communism, or any other "liberal" philosophy, and ask them what they think of Conservatives, traditional values, or any number of other ideals which many people ascribe to. You'll get a mouthful, and, if you're taking the course and offer a contrary opinion, you'll likely receive a poor mark.
Let the liberalism you speak of wilt. It's caused more pain, suffering, economic hardship, and death amongst "the common man" than any other philosphy or political movement in recent history - and that includes World War II.
Socialism and communism better explained by a psychologist than a political theorist.