Big donors are making their voices heard in Oregon's Republican primary for U.S. Senate.
Three super PACs and a traditional political action committee have reported spending at least $956,000 supporting or opposing the two leading candidates, state Rep. Jason Conger and Portland physician Monica Wehby, according to campaign finance records.
A fourth super PAC has registered with the Federal Election Commission, but it has not yet reported raising or spending money.
Enabled by Supreme Court opinions on campaign finance, super PACs can raise and spend unlimited sums on federal races.
Two outside groups funded by social conservatives are backing Conger, and two are backing Wehby. The money has paid for advertisements on television, radio and the Internet, as well as mailers arriving along with ballots in Republicans' mailboxes.
Ballots are due May 20.
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