Cheney was expected to post a big fundraising quarter — she has deep connections with conservatives in Washington, D.C., including those close to her father, former Vice President Dick Cheney (R), and has experience in fundraising from her time running an issue advocacy group.

"Our campaign is off to a powerful start. This outpouring of support sends a loud and clear message to the Washington, D.C., establishment — business as usual just won't cut it anymore," she wrote in the email.

Enzi has struggled with fundraising in the past — he had less than $500,000 in the bank as of last quarter, and has yet to announce his numbers from the past three months.

Polling shows Enzi starts with a big lead in the race, however, and much of Wyoming's GOP establishment has coalesced around him.