The United Mine Workers of America (UMWA) will endorse West Virginia Democrats Joe Manchin and Richard Ojeda in the 2018 midterms, reports Reuters. Manchin is a senator up for re-election, while Ojeda will run to represent West Virginia's 3rd congressional district.

Why it matters: The endorsements of the country's main coal miners' union are a significant indicator of the strength of Trump's base, especially since the president campaigned heavily in 2016 on bringing back America's dying coal industry. The UMWA also endorsed Democrat Conor Lamb in Pennsylvania's special election this month, helping Lamb defeat his Republican opponent in a district Trump won by 20 points.