Worth picked San Diego as one of the 15 most dynamic cities in the U.S. thanks in large part to how well the city managed its symbiotic economic relationship with Mexico. President Trump’s border wall and tariffs threaten that tie today, but Mayor Kevin Faulconer, a Republican, is fighting back. In January of this year, he pledged “unwavering support” for San Diego’s close ties with its neighbor to the south. “Keeping trade moving in both directions safely and securely is important to San Diego’s economy and helps create local jobs,” he told the San Diego Union–Tribune.