PARIS — President Donald Trump’s Russian business ties, Jared Kushner’s relationship with the Saudi crown prince, Ivanka Trump’s Chinese trademarks — all could come under new scrutiny by the Democrats when they take over the House of Representatives. While Trump retains broad power over national security and U.S. foreign policy, the midterm election result exposes him to congressional investigations that could reverberate beyond American borders. Now that they have taken control of the House from the Republicans, Democratic leaders of many committees will have subpoena powers enabling them to obtain documents, email and testimony. If the White House doesn’t block such requests in court, they could shed light on Trump’s international business empire — and what role it’s playing in U.S.