WASHINGTON — A conservative operative trumpeting his close ties to the National Rifle Association and Russia told a Trump campaign adviser last year that he could arrange a back-channel meeting between Donald Trump and Vladimir Putin, the Russian president, according to an email sent to the Trump campaign.A May 2016 email to the campaign adviser, Rick Dearborn, bore the subject line "Kremlin Connection." In it, the NRA member said he wanted the advice of Dearborn and Sen. Jeff Sessions of Alabama, then a foreign policy adviser to Trump and Dearborn’s longtime boss, about how to proceed in connecting the two leaders.Russia, he wrote, was "quietly but actively seeking a dialogue with the U.S." and would attempt to use the NRA’s annual convention in Louisville, Ky., to make "?‘first contact.’?" The email, which was among a trove of campaign-related documents turned over to investigators on Capitol Hill, was described in detail to the New York Times.Robert Mueller, the special counsel investigating Russian interference in the election and possible collusion with the Trump campaign, secured a guilty plea on Friday from Trump’s first national security adviser, Michael Flynn, for lying to the FBI about contacts with Moscow’s former ambassador to the United States. But those contacts came after Trump’s improbable election victory.The emailed outreach from the conservative operative to Dearborn came far earlier, around the same time that Russians were trying to make other connections to the Trump campaign. Another contact came through an American advocate for Christian and veterans causes, and together, the outreach shows how, as Trump closed in on the nomination, Russians were using three foundational pillars of the Republican Party — guns, veterans and Christian conservatives — to try to make contact with his unorthodox campaign.Both efforts, made within days of each other, centered on the NRA’s annual meeting and appear to involve Alexander Torshin, a deputy governor of the Russian central bank and key figure in Putin’s United Russia party, who was instructed to make contact with the campaign."Putin is deadly serious about building a good relationship with Mr. Trump," the NRA member and conservative activist, Paul Erickson, wrote.It is not clear how Dearborn handled the outreach.