The race to replace retiring Sen. Max Baucus (D-Mont.) is a top priority of both parties, and could prove decisive in which party holds Senate control after the 2014 election.
The poll shows recruitment will make or break the race.
If Schweitzer doesn't run both Daines and Racicot would have huge leads over other potential Democratic challengers, but if he does run and neither top-tier Republican challenges him the former governor would start off with a similarly large lead over other opponents.
The automated poll of 807 Montana voters was conducted from June 21-23 and has a margin of error of plus or minus 3.4 percentage points.