As Joe Lieberman and Ned Lamont were getting ready for their final debate today with Republican Alan Schlesinger, their campaigns traded barbs on money. This weekend, as Mr. Lamont donated another $2 million to his campaign’s coffers — grand total so far: $12.7 million — the campaign raised questions about $387,000 the Lieberman campaign reported spending on “petty cash” to pay for “volunteers” in the field during the days before the primary campaign.

Today, the Lamont campaign filed a complaint with the Federal Elections Commission and called on the Lieberman camp to release the petty cash journal it is required to keep.

The Lieberman campaign said it was in full compliance with the law and said, bluntly, it would release the journal when Mr. Lamont releases the joint tax returns he filed with his wife. (And each campaign has an online petition calling for the other side to do as requested.)

A campaign finance expert outside both campaigns tells us that while it is rather curious Mr. Lieberman has so much money listed in petty cash, it is probably not illegal.