President Trump on Tuesday granted a pardon to Ross Ulbricht, the creator of the Silk Road drug marketplace and a cult hero in the cryptocurrency and libertarian worlds. In doing so, Mr. Trump fulfilled a promise that he made repeatedly on the campaign trail as he courted political contributions from the crypto industry, which spent more than $100 million to influence the outcome of the election. A Bitcoin pioneer, Mr. Ulbricht, 40, was sentenced to life in prison without the possibility of parole in 2015, after he was convicted on charges that included distributing narcotics on the internet. “I just...