Michael Cohen's testimony prompts a new question: In web of Trump investigations, is anyone safe?

The first domino was an eager Trump campaign operative who shared what sounded at the time like an idle boast that Russia had dirt on Hillary Clinton.

The conversation between George Papadopoulos, a largely unknown foreign policy adviser for Donald Trump’s then-fledgling bid for the White House, and an Australian diplomat took on significance only later, after the Democratic National Committee said Russian hackers had stolen troves of emails. It became the first inkling that “Americans might be working with the Russians,” former FBI Director James Comey would later...