On Monday, May 18, Governor Gregoire will be signing the bills expanding domestic partnership in Washington state. Once the provisions go into effect (some --the ones that cost the state the most money-- are not effective until 2014!), registered domestic partners in Washington will have all the state-based consequences of marriage. The Washington approach mirrors that of California's domestic partnership laws.
This is a good time to note a way in which Washington state is unique in the US. Both married and unmarried couples (different-sex and same-sex) get the same rules of property division when they split up. By virtue of a number of state supreme court opinions, community property principles apply to the breakup of cohabiting couples even if they have not married.
The American Law Institute recommended almost a decade ago, in its Principles of the Law of Family Dissolution, that the financial consequences of ending a domestic partnership and ending a marriage should be the same. They used Washington state as one of their models. (Australia has such rules as well).
To me, this is a no-brainer. The division of property always looks backwards at how the couple lived. A court can do that just as easily for an unmarried couple as for a married couple. The reason we don't apply general contracts and property law to divorces is that special rules are needed to prevent injustice; a spouse may act for the common good of the family or household, and without special rules (s)he could be left with nothing. Well the same holds true for unmarried partners, and they deserve justice as well.
Consider this fact, which continues to amaze me: In British Columbia, in 1972, the courts ruled that when an unmarried couple splits up one partner can be required when appropriate to provide some ongoing financial support to the other partner. More than thirty-five years later, not a single American state has such a rule. Even Washington state. But at least they have gone part of the distance towars recognizing that marriage (and now registration as domestic partners) shouldn't be the dividing line between relationships that count and those that don't.