"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."
-the First Amendment
Funny thing about this Amendment, while it is one of the most important it is one of the least understood. See there is no "Freedom of protest", and while the Government can not establish a Religion like the Atheists say, it can not also ban displays of religion. The United States Government can't create a church, like the Anglican, or the Church of England. But on the other side I can exercise that religion, and display it however I choose. So in theory any Cross on public land can not be forcibly taken down.
Also notice something else, it says the Congress can't do that. It unfortunately doesn't say diddly about the Courts, which is exactly where this very Amendment is being Undermined ironically enough by claiming this amendment. See the Courts can order just about anything. Congress can no more take down a war memorial than it can erect one if it has religious overtones. As I said though the Courts can. Also technically Public land is owned by. . . the public. It creates something of a Logical feedback loop. The land is owned by the public, a majority of the public firmly believe in Abrahamic faiths, a majority of the public are fine with religious displays, and since Congress didn't put it up it's ok. BUT since the United States Government can't establish a religion, then you are left with a question of "does displaying the Cross (or any other religious symbol) mean the US Government is endorsing said religion?" I personally do not buy the second part for a second, but that is the Legalise logic jam that has caused rather simple things to become actually tremendously complicated. Also it should be noted that "Separation of Church and State" appears nowhere in this amendment or in the Constitution. Rather that phrase comes from ONE LETTER written by Thomas Jefferson, and has been taken so out of context its a wonder no Judge has stopped a court preceding to call bullshit.
"Abridging the Freedom of Speech". It is funny how that keeps coming up. Ok, let's be very clear you can say whatever the hell you want to whenever the hell you want to. I don't care if you're in the American Nazi Communist Black Panther Gay Pride Party, it doesn't matter what you want to or have to say you can say it. But you see there's a couple of catches. First and foremost, no one has to provide you a platform for your speech. If you're a rocker and you get on stage and bad mouth the sitting US president, that is totally your right. Its just as much the crowd's right to boo you. Also it does not mean that you can in any way coerce another Citizen to have to listen to you. Free Market Principles will sometimes bite you in the ass here. Like I said, you can Say whatever you want, doesn't mean you're protected from the consequences.
Another catch is your Freedom of speech ends rather abruptly so when you infringe on another person's rights. So the second you advocate Violence, or the second you put out information that will cause harm to another Citizen (financial or bodily) you have crossed the line and that freedom and the protections of this Amendment are gone. A great example, and just recently, Spike Lee tweeted the (wrong) address of George Zimmerman who allegedly shot and killed Tayvon Martin. The people who lived there were harassed to the point they had to flee their home. In this particular case it is a civil Liability, and no doubt Mr Lee will pay dearly for that stunt, but had it been the correct address, and George Zimmerman had been hurt or killed because of what Mr Lee had done, he would become criminally liable. In essence one tweet would put him up for Negligent Homicide (manslaughter).
It must also be acknowledge that Secrets are a part of statecraft. No state can effectively conduct any military operations without secrets. Indeed some aspects of our national defense such as counter terrorist or submarine warfare depend on such secrets. If you leak or "blow the whistle" on such operations that place service members at risk, that is most certainly not protected speech. Indeed I have heard moonbats try to say that PFC Bradley manning, the yahoo behind the Wikileaks fiasco, was just exercising his freedom of speech. Nope. He put soldiers in danger, and the information he released literally got informants killed. Also on a side note when you fall under the Uniformed Code of Military Justice. . . well to put it bluntly most of the Rights and Privileges you have as a US Citizen disappear. So you really can't hide behind any Amendments there.
An important part of this Amendment is regrading the Press. While I would truly like to believe that the "4th Estate" is neutral, and is only concerned about the truth, we have seen time and again that this is not the case. It is quite interesting that a lot of the Partisan sources of news have called for laws that demand "Fair" reporting. The "Fairness Doctrine" which was almost enacted by the FCC would in essence violate the First Amendment, by forcing news to have opposing view points. The Irony is that this is a Liberal doctrine. The short version is that you can not force the Media to censor itself unless it is about to reveal something that is harmful (see Secret) or untruthful. Also it should be noted that while the Government can't censor any reporter legally, it does not follow that it has to support them. That consequences thing. (See Michael Yon)
Lastly the "Right to Peaceably Assemble". To be very clear while it is insinuating that this is "Protest" there is no "right to protest" anywhere in the constitution, nor to my knowledge anywhere in the writings of the Founders. Again this right goes out the window when that peace is shattered. If you sit down and sing and have drum circles that's fine so long as you have permits, and are not in anyway impeding your fellow citizens. See Occupy Wall Street which sure started off Peaceful enough, broke this almost immediately. They took over public land, and how the assembled soon became a health hazard both to themselves and the citizens that passed by them. Also the livelyhood of those actually working in and near the financial district was affected by their actions. There were no Permits filed, or fees paid, and thus the Taxpayer was out for the overtime the Cops had to pull. That they got violent (as such people so often do) would have been grounds for the police to round everyone of them up and throw them in jail. Occupy Oakland's seizing port facilities pretty clearly violated "Peaceably" and the only ones that should have been chanting "shame shame shame" was the rest of Oakland that had to put up with their antics. Again, remember your right goes up to a point. Once you cross that, the right is gone!
As far as petitioning the Government, that one is pretty simple. We have the Courts, and believe it or not you can make an appointment with your Representative or Senator. They pretty much have to see you if you feel that you have a grievance. They may brush you off to their staff but if they don't even give lip service to your complaint that's a big no no. It may cost you. You may not get the reply you want. The whole country can be against you, but darn it if you feel strongly enough about an issue, the US Government has to listen.
This Amendment should be simple enough, but it is not. There is a reason though, that it is the First one. No society is Free without the ability to speak. We may not always like what is said or how it is said, and sometimes the people saying it can be downright loathsome, but in the end we need to be able to say what we need to say. Without that ability, we would fast become a tyrannical dictatorship. Even though it is rather tiresome to have to listen to someone whine endlessly about how their Free Speech (which if you think about it actually costs a hell of a lot) is being infringed upon, we must always be vigilant. There may come a time when even your opponents are having their freedoms infringed upon, and such a case must be taken seriously, lest eventually your freedoms be taken away.