.@DarrellIssa is a very good man. Help him win his congressional seat in California.— Donald J. Trump (@realDonaldTrump) November 1, 2016
Some of Trump's supporters don't like Republican politicians and would be just as happy if they lost and there was a Democrat in the seat. They want to punish Republican politicians for disloyalty. If Trump tells them to vote for someone, they're more likely to vote for that candidate. If Trump tells his supporters to vote for down ballot Republicans across the board Republicans should do very well. The Republican voters who supported Issa in the past who might vote Clinton this time should still support Issa even if Trump is endorsing him. They are still Republicans. Aaron Blake at the Washington Post thinks this is bad for Issa.
FWIW, CA-49 is a swing-y district that Obama carried in 2008. May not be helpful there. https://t.co/l8TRghtAOE— Aaron Blake (@AaronBlake) November 1, 2016
The media, at least sometimes, is accepting that Hillary Clinton is winning the race by a similar margin than Barack Obama won in 2012. Right now it looks like less. Yet they act like Trump is going to get killed in swing districts. Mitt Romney won this district by 7 points. If Trump loses by a similar margin as Romney did, his votes have to come from somewhere. They're likely to come in similar margins as Obama-Romney had. Yes, Donald Trump is very unpopular in California and will get killed here. But Matt Romney got killed here and still won CA-49.
Mitt Romney won the district with 153,856 votes. Issa won by nearly 10% more but only got 159,725 votes. That's because roughly 20,000 people who voted for President didn't vote in the congressional race. Issa would've won with the number Mitt Romney had and would win this election if he gets the same number of votes Donald Trump gets here. I think this is a big positive for him.