Dallas Mayor Eric Johnson is warning that the rise of socialism poses a "grave threat" to American cities, drawing a sharp contrast between that movement and the pro-business, free-market approach he says has helped Dallas thrive.Johnson joined FOX Business’ Stuart Varney on "Varney & Co." to discuss the rise of socialism in U.S. cities and why he believes it poses a broader threat to the country’s economic future.Johnson, who served as a Democratic state lawmaker before being elected mayor in 2019 and switched to the Republican Party in 2023, argued that the political divide extends beyon...