As expected, Montana Representative Scott Reichner (R-Bigfork) has now introduced his top-two open primary bill. See here to read the bill, HB 436.
Even though the bill is very lengthy, it seems to have skipped over two potential problems: (1) It says that anyone who gets 50% or more of the vote in the June primary is elected. This proposal violates federal law, as applied to congressional elections. The U.S. Supreme Court ruled unanimously in Foster v Love, 522 U.S. 67 (1997) on this point. The bill has an exception but the exception only relates to county office, not Congress; (2) the bill does not re-define “political party”. The existing definition of “political party” is a group that “had a candidate for a statewide office who received a total vote that was 5% or more of the total votes cast for the successful candidate for Governor in either of the last two general elections” or a group that submits 5,000 signatures. But under the bill, parties would no longer have candidates, except for President, so presumably parties would go off the ballot unless they meet the vote test for President.
The bill has an provision that says when two or fewer candidates file for an office, there is no primary and the two (or fewer) candidates for that office only run in November.
The bill handles presidential primaries, and elections for party office, by providing that the section of the ballot concerning those two offices should be somewhat separate, and voters could only vote in that section of the ballot if they place a check-mark on the ballot indicating membership in one particular party. The legislative analyst has suggested that this part of the bill may not be sufficiently protective of party freedom of association and that this part of the bill might be held unconstitutional.
HB 436 is very lengthy and it hasn’t been easy to analyze it with great care; perhaps commenters who are interested in details and who are careful readers will have greater insight into the bill.