Soon after he assumed office, Trump signed a letter that has been standard since the Clinton administration and before that reflected a verbal policy going back to the Nixon administration.
Israel does not acknowledge its nuclear weapons capability and, under the agreement, neither does the United States. The agreement precludes U.S. pressure on Israel to divest itself of its nuclear weapons capability. In exchange, Israel agrees not to test or threaten to use its nuclear weapons.
A number of non-Israeli experts have determined that Israel has the capability to arm 200 missiles with nuclear warheads. Israel is not a signatory to the nuclear nonproliferation treaty.