Peters, the likely Democratic nominee to replace retiring Sen. Carl LevinCarl Milton LevinSen. Gillibrand, eyeing 2020 bid, rankles some Democrats The Hill's 12:30 Report Congress needs bipartisanship to fully investigate Russian influence MORE (D-Mich.), has $1.8 million cash on the hand, his campaign announced in an email to supporters. That's a good start for the congressman, who's known as a strong fundraiser.

"It's exciting to see the outpouring of support from Michiganders who back Gary's fight to stand up for middle class families and small businesses in the U.S. Senate," Peters for Michigan campaign manager Julie Petrick said. "This strong showing is a testament to the work Gary's done to put Michigan first and the leaps we're making as a team to build the strongest grassroots campaign Michigan has ever seen."

Peters's most likely GOP opponent, former Michigan Secretary of State Terri Lynn Land (R), has yet to release how much she raised since she announced her bid in early June. The fundraising quarter began in April and ended at the end of June.