India, Oct. 30 -- Control of the US Congress for the last two years of Donald Trump's second term could be decided on November 3 in roughly a dozen Senate contests and a few dozen House districts, where polls indicate that either party could win.

If Democrats take the House in the midterm elections, they could block parts of Trump's legislative agenda, open investigations and step up oversight of his administration. Control of the Senate would let them shape the confirmation of cabinet officials, federal judges and any Supreme Court nominee. If Republicans keep both chambers, Trump would have a freer hand for his legislative priorities, although narrow majorities could still slow the passage of bills.

Republicans hold the Senate 53-47, ...