US midterms – The races to watch

Americans vote on November 3 in midterm elections that will decide whether President Donald Trump’s Republicans retain control of Congress or spend the final two years of his term confronting Democratic majorities.
High living costs, the war with Iran and Trump’s poor approval ratings have helped Democrats expand the electoral map, with unusually tight contests even in Republican strongholds.
But polling errors, redrawn districts and record campaign spending make the outcome uncertain.
– The arithmetic –
Republicans hold a 53-47 Senate majority. Democrats need a net gain of four seats to take the upper chamber of Congress. A 50-50 tie would leave Republicans in charge through Vice...