When the Democrats take over the U.S. House of Representatives in three weeks, their first order of business is expected to be a wide-ranging bill about political corruption, voter disenfranchisement and cleaning up campaign finance. An outline of the bill, titled H.R. 1, shows it would require presidential candidates to disclose their tax returns, which Trump has refused to do despite decades of precedent. The bill calls for automatic, early and online national voter registration, as well as an end to partisan gerrymandering of House voting districts, the practice of changing electoral district boundaries to favor a party. Members of...