Sen. John McCain faces questions in a defamation lawsuit about leaks leading to publication of the now-infamous dossier that alleged Donald Trump’s campaign had connections to Russian operatives, McClatchy has learned.

The dossier compiled by former British spy Christopher Steele and his London firm, Orbis Business Intelligence Ltd., amounted to a collection of uncorroborated reports of collusion gathered as political research for sale to Trump’s opponents. It proved explosive when published by online news site BuzzFeed on Jan. 10.—More…