Earlier quoted context omitted.
$38 billion. woah. if US continues to give Israel unconditional aid then it will start to look like a vassal state https://en.wikipedia.org/wiki/Vassal_state
It's primarily a subsidy for American weapons manufacturers (from whom the Israelis have to make purchases), mixed with a hefty R&D budget for new military technology like Iron Dome.
All observation of U.S.-Israel relations since 1967 indicate that it's driven by a very strong ideological (and perceived electoral) component. In fact it's hard to think of a single case of a ("friendly") country for which the degree of U.S. support is less ideological.
Pork barreling plays a role for sure as well, but it's definitely second fiddle.