WASHINGTON • Missouri state Sen. Maria Chappelle-Nadal was fined $15,000 by the Federal Election Commission for violating federal campaign law in her 2016 primary challenge of Rep. William Lacy Clay.

“It was an honest mistake,” said Chappelle-Nadal, a Democrat from University City who signed a “conciliation agreement” with the FEC admitting the violation. “I was helping a lot of people that I wanted to get elected.”

The complaint was filed in July 2016 by Michelle Clay, the congressman’s sister and campaign manager. The agreement, which was obtained by the Post-Dispatch, alleged that Chappelle-Nadal used a state campaign account, which has fewer restrictions on the amount of money and the source of that money than a federal campaign, to bolster her federal office challenge of Clay, D-St. Louis.

The document, which Chappelle-Nadal signed on July 10, says “Missouri allows state candidates to receive contributions that would be impermissible under the Federal Election Campaign Act of 1971,” which, among other things, bans direct contributions from labor unions and corporations. The agreement says Chappelle-Nadal’s congressional campaign “accepted contributions in amounts above the contribution limits stated in the Act.”