The idea that the New York legislature might end fusion has drawn reactions from non-New Yorkers. This New York Times story mentions that Senators Bernie Sanders and Elizabeth Warren have expressed support for New York’s existing law. The story does not mention it, but both Vermont and Massachusetts also allow fusion, via write-ins in primaries.
Many opponents of fusion claim that New York is one of only three or four states that permits fusion. But actually, fusion is permitted (although sometimes in a restrictive way) in Connecticut, Idaho, Massachusetts, Mississippi, New Hampshire, New York, Oregon, Pennsylvania, South Carolina, and Vermont. Also fusion is permitted for president in approximately half the states. Many state anti-fusion laws do not apply to presidential electors. For example, in 2016, Donald Trump was listed on the ballot in California as “Donald J. Trump, Republican, American Independent.” Thanks to Steve Kamp for the link.