It is hardly a mere border barrier if one prevents the passage of just about anything into the area in question.
Does the US prohibit food the transfer of food and medical supplies and fuel into mexiko?
If it would, it would indeed be an act of war. However it obviously does not.
Another interpretation is that Gaza is not a souvereign state and therefore cannot be blockaded. This would put Gaza as an area occupied by Israel. According to the Geneve conventions, an occupying power has to care for the people it is occupying, also the Geneve convention explicitly prohibits collective punishment. If one claims to the theory that Hamas is not a state, Israels blockade is a war crime. If one adhers to the theory that Hamas is a state or something statelike, Israels blockade is an act of war.
Also, a bit of chronology may be in order: According to Haaretz, an Israeli newspaper the renewed conflict began of Nov. 4 when Israeli troops raided parts of Gaza in an effort to destroy tunnels, killing 6 Hamas members in the process.
(An act of war but not a war crime if you assume that Hamas is not a sovereign entitiy)
Link:
UN: Israel's border closures leave us with no food for Gaza - Haaretz - Israel News
To this the Gaza insurgents retailiated with rockets, which made Israel close off the barrier for humanitarian goods too.
Personally, I think that closing of an area for humanitarian goods coming from a 3th party is what is the line between a strict border control (to which Israel is entitled too) and a blockade (to which it is also entitled too, however it is an act of war, and therefor justifies a war response).
to make an example: The Berlin Wall was not an act of war.
The Berlin blockade was an act of war, however the US decided that it would not respond with force of arms. The Soviet Union also decided that it would not enforce its blockade with force of arms (they had enough anti air around Berlin), which was what saved the world from WWIII.
Considering lying to the red cross:
Do you really assume that Hamas, which controll like no territory, whose leaders are in hiding and whose structure is very decentralized, has the same ability of lying and getting away with at that Nazi Germany had at the peak of its power?
How did the horribly hurt children end up in the hospitals? Do you stipulate that hamas shot them? The grasp of Hamas if fairly volatile, they can hardly afford to alienate the population by doing such things.
Apart from that, please put yourself in the imaginary situation of an American Guerillia fighter fighting to free Manhattan from an evil UN occupation. Assume that you cannot get off Manhattan easily. Precisly where do you intend to place any fighters? There will be next to no place where there would not be civilians near by, and, if the situation is a carbon copy of Gaza, there would be no opportunity of evacuating any civilians prior to the outbreak of hostilities.
From what I got, some alleged Hamas units are wearing identifiers, some are not. However, Israel claims that everyone looking like firing at them is Hamas, when they in fact may have been:
A) Another organisation apart from hamas
B) Someone caught up in the crossfire/confusion
C) Actually was Hamas and tried to cover in the population
It is also likely that Hamas has non-Hamas Subdivisions (which would not have identifiers) which, while claiming that they are someone else, are actually embedded in the Hamas chain of command.
There is a lot of fog of war in urban warfare, and even more strategic fog of war if elections are involved. Apart from information that shows the enemy in a positive light, I take everything with a huge bit of salt.
Cheers,
Mightypeon