Walter M. Shaub Jr., who is resigning as the federal government's top ethics watchdog on Tuesday, said the Trump administration had flouted or directly challenged long-accepted norms in a way that threatened to undermine the United States' ethical standards. It's hard for the United States to pursue international anticorruption and ethics initiatives when we're not even keeping our own side of the street clean. It affects our credibility," Mr. Shaub said. "I think we are pretty close to a laughingstock at this point." Mr. Shaub called for nearly a dozen legal changes to strengthen the federal ethics system: changes that, in many cases, he had not considered necessary before Mr. Trump's election. Mr. Shaub recommended giving the ethics office limited power to subpoena records, as well as authority to negotiate prohibitions on presidential conflicts of interest; mandating that presidential candidates release tax returns; and revising financial disclosure rules. Hui Chen, who served until recently as an ethics expert in the Justice Department's Fraud Section, said Mr. Shaub's proposals would give the office greater independence and power to police actions by top federal officials. Mr. Shaub, who is taking a job at a nonprofit group called the Campaign Legal Center, said he had never wanted the role of challenging the president. "I would not have picked this fight," said Mr. Shaub. "But I have never been one to shy away from bullies."