A U.S. National Guard officer pleads guilty to charges related to a secret second marriage and the alleged misuse of public funds. According to reports, Major Collin Welch married a woman he met while posted in Mongolia while he was still married in the United States. Prosecutors allege that the officer used a government travel card and forged documents to facilitate the second marriage and support a double life. The accounts describe a scheme in which falsified records and official resources were used to enable travel and related arrangements connected to the second relationship. The reports are consistent that the case involves forged documentation, the use of government payment tools, and conduct that continued while the officer maintained his existing marriage. The outlets also note that the plea is part of the legal proceedings stemming from the investigation by U.S. authorities. Specific sentencing details and the final outcome are not included in the provided excerpts.