Democrats are worried about Latino voters in the midterms, fearing that weak efforts to energize a core element of their base could imperil their bid to win control of Congress in next month's elections. From the Sun Belt battlegrounds of Nevada and Arizona to sprawling turf wars in Texas and Florida, there are signs that the Hispanic vote - which party leaders have long hoped would be the foundation of future electoral success - has yet to flourish in their favor this year. Recommended Video Although President Donald Trump and Republicans have embraced policies and rhetoric hostile toward Latino immigrants,...