This San Diego Union Tribune story says that because Congressmember Darrell Issa, a Republican, is retiring, there may be two strong Republicans running to replace him. Because there are also four strong Democrats running for the same seat, the story speculates that the two Republicans might capture the first and second place slots in June 2018, leaving no Democrat on the general election ballot, even though Hillary Clinton carried the 49th district by seven points in November 2016 and Democrats had been hoping to win this seat even before Issa said he wouldn’t run again.