It seems like the Republicans aren't even trying in Maine.
"Unlike Iowa or several other state caucuses, the Maine caucuses are on different days: Republicans on Saturday and Democrats on Sunday. Republicans have 22 caucus locations around the state, while Democrats will have well over 400.
Whats more, absentee ballots are allowed in the caucuses. More than 20,000 of them were submitted by Wednesdays deadline to the Maine Democratic Party, according to its executive director. Party leadership has said they see this as an omen for high turnout on Sunday.
The Republicans have allowed ballots for active military, disabled veterans, and national guard members."
https://www.bostonglobe.com/news/politics/2016/03/04/depsite-trump-visit-maine-caucuses-expected-low-key-contests/3NrHlKFgaPsyb3VaDE3q2K/story.html#comments
Only 22 Republican caucus locations, but the Democrats have over 400. Democrats allowed all party members the ability the submit absentee ballots (I submitted one myself). Republicans only allowed absentee ballots for active military, disabled veterans, and national guard members. Do they have policies like this in other states or is it just Maine?