Before answering this question, we should ask ourselves our selves a question what is terrorism?
This might create problem, because each person and each government and each religion count something else as a terrorism.
Due to my opinion terrorism is planned and prepared attack by a group of people on unwarned civilians at a peacetime.
From my point of view this type of resistance is totally unacceptable.
Attack at a peace time on civilians is never justified as it results in deaths of innocent people.
But this is where the problem begins- for the attackers it is the holy must but for those attacked it is totally unacceptable act of terrorism which should be revenged.
This is the problem of different point of views- one side always see the act of terrorism unacceptable and the other the only acceptable solution.
If we have a look at the recent problem when the USA were attacked (most probably) by Usama bin Ladens Al–Kajda(the base), we can see that two groups with two different opinions rose up: part of the Islamic world for which Bin Ladens attack is heroism against the “Big Evil” and the “Western” civilization which wants revenge and finds the attack to be terrorism.
We should try to find out where the terrorism rises. I think that terrorism rises when one group has requests on the other and when the requested one does not want discuss or does not want to fill the request. This is what happened in New York on 11th September.
Part of the Islamic world thinks that there is no other way to fight the capitalists than this so called “Heroic attack”. The “Western” civilization, according to the Islamic radicals, consume too much, exploits the world and tries to teach the rest the “Western” way of life. They say that dialogue is impossible- which is partly true as the USA certainly are not going to change their way of life neither to stop making business all around the world.
As the Islamic radicals could not fight the “open war”(soldiers, tanks, bombing cities etc.), they started the terrorist attacks. Actually for them these are not terrorist acts while the bombing of Afghanistan by the USA is an terrorist act. Taliban supports Al-Kajda and other terrorist groups to stay in power, to keep their people uninformed and to get even richer.
These people do not realy fight a religious war, they just use religion to keep masses of people under control and make them obey the rules. There are two main reasons to use violence: either to get into or increase power, or to get richer.
Though I partly agree that the USA exploits other countries and on impossibility of dialogue, I certainly do not agree with the attack on New York.
But if we take a look on the previous Chechnyan crisis which ended up by Chechnyan terrorist attack and kidnapping of a Russian bus, we must admit that though terrorism is never justified, it is sometimes the only possible solution (at least from my point of view).
Is terrorism justified in the case of Alexander II?
I think that in this case terrorism is justified. It was the only possible solution to resist the government. In this case the dialogue was almost impossible as the Tsar certainly was not going to give up his power.
I think that they could not do anything else to weaken his position.
But by the way: this terrorism could not make any real success- if the Nicholas II would give up his power, they would most probably kill him. If not the terrorist attacks would go on and killing of people would not stop.
Anyway, the probability of killing the Tsar was quite low as he was protected quite well.
But it could show the people that the opposition is possible and it could help to create large up-rises of resistance and could help to seed the seed of resistance inside Russia.
In this case, terrorism not aimed at the civilians, was, due to my opinion, justified.