Missouri state Sen. Jeff Smith (D) pleaded guilty to two counts of obstruction of justice in federal district court and then resigned his seat in the Legislature on Tuesday five years after he illegally coordinated the release of negative postcards in his 2004 primary against now-Rep. Russ Carnahan (D) in the 3rd district.Smith — a former college professor who was the subject of a much-heralded documentary about his 2004 primary campaign titled “Can Mr. Smith Get to Washington Anymore?— — now faces 15 to 21 months in prison, according to the sentencing guidelines laid out in a plea agreement he signed with the U.S. Attorney’s Office.In July 2004, the independent organization Voters for Truth distributed 25,000 postcards to 3rd district voters that skewered Carnahan. Carnahan’s campaign subsequently filed a complaint with the Federal Election Commission alleging that Smith’s campaign had illegally helped create and finance the distribution of those fliers.In his plea agreement, Smith admitted to submitting false statements to the FEC, which closed the case in 2007 citing a lack of evidence. Smith also admitted to trying to mislead FBI investigators who took up the case earlier this year after new evidence emerged.“When questioned [by the FBI] I stood by our 2004 account and encouraged my close friend to do so, misleading the authorities. Today I am taking full responsibility for my mistakes, and have pled guilty to obstructing justice,— Smith said in a letter announcing his resignation from the state Senate on Tuesday. “I apologize to my constituents, my staff, my Senate colleagues, my supporters, and to Congressman Carnahan.—Carnahan said Wednesday that he was never contacted by the FBI about its investigation. He also noted that if Smith had told the truth to the FEC, he would not be facing prison time.“On one hand, it’s very sad. … On the other hand, the system worked,— Carnahan said during a press conference on an unrelated topic Wednesday. “Had the rules been followed, this wouldn’t have happened in the first place. And had the matter been resolved through the FEC process, it may have resulted in just a fine.—Carnahan won the 2004 open-seat race to succeed Rep. Dick Gephardt (D) in the St. Louis-area district. He won the 10-way Democratic primary with 23 percent of the vote. Smith came in second with 21 percent. In addition to Smith, his former campaign treasurer Nick Adams and state Rep. Steve Brown (D), who helped out on his Congressional campaign, both pleaded guilty to obstruction of justice charges. All three men are scheduled to be sentenced in early November.