SOMETHING WAS MISSING. When Barack Obama met with Vladimir Putin this June at the G-8 summit in Northern Ireland, congeniality wasn't the only thing that was noticeably absent; both leaders' neckties were AWOL. The gesture apparently came at the behest of host and British Prime Minister David Cameron, who lobbied for a more relaxed dress code at the two-day international conference. The new look immediately raised eyebrows in the British press.

However, this was hardly Mr. Obama's first public appearance sans neckwear. "Obama...