A March 15, 2006, Wall Street Journal article points out the difficulty that spouses and former spouses are having in seeking Innocent Spouse Relief from the IRS. When you sign a joint income tax return with your spouse, you and your spouse are jointly responsible for the taxes, interest or penalties on those returns unless you qualify for innocent spouse relief. That means that under most circumstances, the IRS can collect the entire amount owed from either party.
When you claim the “innocent spouse” defense, you argue that you did not know and had no reason to know about any under reporting of income or other wrongdoing associated with the filing of the return and that therefore you should not be held responsible for paying any additional taxes, penalties or interest due.
According to the article the IRS has taken a renewed interest in enforcement, due in part to growing concern of the budget deficit. The article sites a recent report that states that of the nearly 50,000 innocent spouse claims received by the IRS in 2005, only 21% were allowed in full and another 8% were partially allowed.
The moral to the story: if you have even a hint of impropriety, do not sign a joint return. As a divorce lawyer, I would also add that if a divorce is imminent then before signing a joint return, talk to your lawyer about the implications first.
Note: I would link to the Wall Street Journal story but it is not available on wsj.com without a subscription. If you are a subscriber and have acces to the Journal online, you can go to the above link and do an article search for “Innocence in Tax Fraud” and it will pull up the article.
Also, you can download the IRS publication describing and explaining Innocent Spouse Relief here.