The strategy has already created some strange bedfellows: An outside group run by former Republican Governors Association officials has spent about $250,000 on advertisements touting Dill as "a Democrat you can feel good about."
Expect the NRSC advertising to strike a similar balance between boosting Dill and cutting down King. The party doesn't have terribly high hopes for Maine, but they believe they can move the needle, with the goal of converting Romney voters to Summers backers.
If a Summers victory looks increasingly plausible, it would put the Democratic Senatorial Campaign Committee in a bind: They have so far avoided the race, given their rooting interests in King over Dill. If they had to begin advertising, it would prompt more uncomfortable questions over their loyalties.
Maine is only the third state in which the NRSC has begun running television ads, after North Dakota and Montana, two other states with inexpensive ad time. The committee has advertising time reserved in Virginia and Wisconsin, but it hasn't begun airing ads yet.