Not sure if you are being serious. US / Israeli relations are currently frayed, but have been some of the most stable in the post WWII era minus them attacking a US spy ship in 1973 and killing a bunch of Americans. Being pro-Israel has been a standard requirement for anyone running for President since Israel was formed.
Netanyahu has pushed for more settlements in Palestenian areas, destabilizing an already unstable area. He has pushed into Gaza and Lebanon with the IDF. Which is destabilizing. A lot of Israeli's are not in favor of this, and think these actions make them less safe.
Netanyahu is pushing for a military solution to Iran's nuclear program. You can interpret that to mean he wants the US to provide the bulk of the airstrikes needed to accomplish this. Netanyahu has a lot of friends in the US who want military strikes, too. Most of them have no skin in that game.
Further, I find it interesting that one of Netanyahu's biggest financial backers is Sheldon Adelson. The US citizen who bankrolled various Republican candidates in the 2012 election. He promises to be a huge donor for the 2016 cycle.
That is brief, and off the top of my head. You can find other reasons why who runs Israel is important to the US with minimal research.
