Filing jointly creates spouse or ex-spouse. Put another way, both spouses are equally, jointly and individually liable for taxes, and if the I.R.S. cannot get one, it goes after the other, and sometimes both at the same time.

Thus, long after a couple have divide the goods and go separate ways, the I.R.S. (or any other taxing agency) can pursue either of them to collect what is due. In the extreme, if the I.R.S. determines statute of limitations on the prosecution of tax deficiencies and the recovery of taxes.

Despite the action of a less than honest spouse, but a wife sailing rough marital seas should think twice about a joint tax return.

Few government agencies have an arm as long as the I.R.S. Its claims supersede any marital separation agreements dividing property.

Joint and several liability can make for long-lasting problems in a divorce when one of the spouses filed a fraudulent, dishonest or even inaccurate return and the other spouse, acting in ignorance but good faith, signs on to it.

See also Joint and Several Liability; Innocent Spouse Rule.