Sen. Claire McCaskill (D-Mo.) raised $2.6 million in the past three months, according to the Springfield News-Leader, a strong haul that will help her stay competitive on the airwaves this fall.

McCaskill has purchased $3 million in airtime for the fall, and has $3.6 million left in the bank.

She faces a tough race in the Republican-leaning state against any of the three Republicans vying for the GOP nomination, none of whom have released their fundraising totals yet. The Hill rates the race a "toss-up."