How Trump has affected Orange County

As Donald Trump visits California tomorrow, one place conspicuously absent from his announced schedule is Orange County. The then-presidential candidate visited Costa Mesa to a raucous crowd in April 2016, but ended up losing OC to Hillary Clinton--the first time a Democrat has taken the famously conservative county since FDR in 1936. The county's Republican politicians has largely shied away from Trump ever since save for Congressman Dana Rohrabacher, who now faces a challenger in former OC GOP chair Scott Baugh, who alleges Rohrabacher's close ties with Trump has put him out of touch with the needs of constituents. Meanwhile, recently released figures show that the GOP's share of OC's registered voters continue to fall. What, if anything, can Trump do to shore up the party base in OC?