All would if it is necessary. Not sure if Collins will end up doing so, but I think all others do. McSally and Loeffler have already made that clear in public statements, I think.
P.S. US poliics became stupidly polarized. Compare present situation with Nixon's SC nominees....))). Everyone voted it's conscience then: conservative southern Democrats in Senate voted "for" because nominees were southerners and conservatives, moderate and liberal Republicans - "against", because of ... essentially the same. The most important element of US politics
NOW - FEAR. Fear of financial "retributions" on part of ideologized PACs, fear of primary challenge on part of "ideologicaly "pure"" opponents, and so on...