On Sunday, Public Policy Polling released a survey showing Massachusetts Democratic U.S. Senate candidate Elizabeth Warren with a narrow lead over Republican incumbent Sen. Scott Brown. 

A day later, the U.S. Chamber of Commerce announced that it was spending additional money in Maine to bring down independent front-runner Angus King. Today, reports with the Federal Elections Commission show that Maine Freedom, the Republican group that spent money attempting to prop up Democratic candidate Cynthia Dill, is also dumping more money in the Maine race. 

Is it a coincidence that the increased spending in Maine is coming at the same time as a poll showing Warren’s apparent gains in Massachusetts?

Probably not. 

Maine and Massachusetts are becoming increasingly more important as national Republicans recalibrate their expectations for gaining the majority in the U.S. Senate. Remember that piece in Bloomberg Businessweek about Republican strategist Karl Rove’s meeting with campaign donors?

Here’s what he said:

"But we’re gonna lose, either [Maine] or Scott Brown—we can’t afford to lose both," Rove said.  "If we win both, we’re in great shape. If we lose one, it starts to get a little bit edgy. If we lose two, we’re in real difficulty." 

Rove’s comments are worth remembering as the race unfolds.