The haul is a solid one for a House member in a safe seat, though Pryor nearly doubled that with a $1.2 million quarter. Pryor now has $3.9 million cash on hand. Still, Cotton's strong fundraising totals before he's even announced a campaign shows how well-liked he is by both the GOP's donor class and its Tea Party grassroots, and if he runs, money is unlikely to be a problem.

The race is expected to be one of the most hard-fought of the cycle, no matter who runs against Pryor, though Republicans see Cotton as their strongest option.