To the surprise of many, the estate tax expired on January 1, 2010. It remains to be seen whether Congress will reinstate it before it returns in 2011, but the fact that there is currently no estate tax can have surprise consequences for spouses.

Standard language found in many estate plans could leave spouses without assets via outright distribution or through a marital trust. It is important to check with an estate planning attorney to make sure your estate plan does what you want it to do.

In previous years, estates could pass a certain amount of assets tax-free (up to $3.5 million in 2009). In addition, spouses can receive an unlimited amount tax free. To take advantage of these rules, estate plans often contain a “bypass trust” (or “credit shelter trust”) and a will with language in it that is designed to allow estates to pass without any estate tax. For example, the will may state something along these lines: “I leave to my trustees the maximum amount that can pass free of estate tax and leave the residual to my spouse.” Because there is currently no estate tax, individuals who die in 2010 with language of this sort in their estate plan could wind up leaving nothing to their spouses via outright distribution or through a marital trust.

While most states allow spouses to claim a portion of the estate (usually one-third), even if they don’t receive anything under a will or trust, this can be a time-consuming and expensive process. Similarly, dealing with “disclaimers” and other post-death planning options can be fraught with potential pitfalls.

Some states are considering legislation to fix the problems created by congressional inaction regarding estate taxes, but to ensure your spouse is covered, you should talk to your attorney.