On June 9, the Maine legislature passed LD 231, which lets independent voters choose a primary ballot, even though they are not members of the party. The bill was originally titled as a bill for an “open primary”, but it was amended to say that it is now a bill for a semi-open primary.
The Maine bill is similar to laws in Arizona and Colorado. More common are states that leave it up to each party that has a primary to decide for itself whether to let independents vote in its primary.