system
Given the following post, respond as if you're commenting on Reddit:
human
Why does Israel have such a huge impact on the United States' foreign policy affairs?
gpt
Ok, so this is probably going to get buried, but here goes.

A lot of what's being said is that the US allies with Israel because of cultural similarities, and the large, pro-Israeli lobby in the United States.  These factors cannot be overlooked, but they miss some of the larger picture: Israel plays such a large role in America's Middle Eastern policy because Israel is America's only consistent ally in the region.

Going back to 1683, the Muslim, Middle Eastern, powers were beat up on by the Europeans.  The Ottoman Empire was the cultural Muslim stronghold, and over the centuries it was taken apart and carved up piecemeal by the Europeans.  To give you some idea how bad it was, imagine if Canada and Mexico annexed all of the US east of the Mississippi.  So when WWI came around, the Ottomans allied with the European powers who would help them - Germany - and got demolished.

Britain and France took over control of the Middle East after WWI, and managed to royally piss off a large amount of people living there; the Muslim Brotherhood started to take off about this time as a reaction to British and French aggression.  When WWII came, the Middle East tried to ally with Nazi Germany to throw off the Western Imperialists.  That went about as well as could be imagined.  

After WWII, the state of Israel was created by UN mandate - crucially, the Arab League did not agree.  The entire Middle East banded together in an alliance to destroy it, but the entire armed forces of the Middle East were defeated by 400,000 Jews with bolt-action rifles.  Every single leader who took part in that fiasco, on the Arab side, was killed or deposed.

The regimes that arose following that disaster naturally hated Israel; they also hated the West that had colonized them for generations.  Note that it is the governments that hated the West, not the people.  This led to the Middle East allying with the Soviet Union.

Of course, the specter of the Middle East going communist probably caused Washington to shit its pants.  They scrambled around for allies in the region, and they found one: Israel.  Add in a couple more wars, revolutions, and alliance switching later, and the only constant for America in the Middle East is Israel.  The Arab states switch sides in whatever game of geopolitics is happening based on what's best for them - what's best for them is often not best for the US. Israel, on the other hand, faces danger at the hands of these Arab states every day, causing it to ally with whoever it can get its hands on.

tl;dr  The US-Israeli alliance is one of convenience, though the problems in the Middle East are so intractable that it may as well be permanent.