As a candidate, US president Donald Trump insisted he’d make Mexico pay for a wall on its border. As president, he’s trying to strong-arm lawmakers into funding it. “If we have to close down our government, we’re building that wall,” he said (paywall) at a rally in Phoenix on Aug. 22. Even in normal circumstances passing a spending package is steeped in complexity, and when Congress returns from summer recess on Sept. 5 it will have less than a month to do it. Simultaneously, it must agree to lift the federal debt ceiling by Sept 29 to stop the country...