Yes I they should be able to for national safety reasons. If a bomb is planted on a train but there is a blog about it. Why shouldn't we be able to flag that threat and arrest him before AMERICAN life's are at stake. Just because they can tell you post about your boss you look up weed, why should we care they only flag threats which could save you.
Spying should only be done against ones enemy. Thus the US government should not be spying on its own people. The people of the US should be free from suspicion from the government, unless an individual gives the government a particular reason to investigate them. When one has made themselves an enemy of the state, then there is no reason that the US should not be allowed to spy, however for the government to spy on the citizens on the US at large, it is a declared war on the people. The US government should not spy on its own people.
The government should not be allowed to spy people in the USA because it is a clear violation of our civil liberties. The government does not need to know what I do or think in my everyday life. Our constitution is based on individual freedoms and many patriots have died for those ideals. A government that spies on its people is infringing on those rights and liberties. People have freedom of speach in this country and dont want to worry about what they are saying because the governemnt is spying on their conversations.