The Professional Services Council (PSC), a trade association representing 400 federal contractors, wrote a letter Oct. 28 to Congressional leaders mourning the federal government shutdown, citing its effect on the National Nuclear Security Administration (NNSA) among other agencies. The letter, obtained by Defense Daily sister publication the Exchange Monitor, was addressed to Senate Majority Leader John Thune (R-S.D.), Senate Minority Leader Chuck Schumer (D-N.Y.), House Speaker Mike Johnson (R-La.) and House Minority Leader Hakeem Jeffries (D-N.Y.). PSC said the lapse…