OLYMPIA, Wash. (AP) – The Legislature passed a measure March 4 to expand the state’s domestic partnership law, granting same-sex couples more than 170 of the benefits and responsibilities given to married couples, including property and guardianship rights.

The Senate gave final approval on a 29-20 vote after minimal debate. The bill now goes to Gov. Chris Gregoire, who is expected to sign it.

The measure adds domestic partners to sections of laws where previously only spouses were mentioned, including areas referring to probate and trusts, community property and homestead exemptions, and guardianship and powers of attorney.

The underlying domestic partnership law, passed last year, already provides hospital visitation rights, the ability to authorize autopsies and organ donations, and inheritance rights when there is no will.

More than 3,500 couples have registered as domestic partners since the law took effect last year.

“Our work last year was only a start,” said Sen. Joe McDermott, D-Seattle and one of six gay lawmakers in the Legislature. “Domestic partners still lack the vast majority of protections granted other couples.”

The measure makes dozens of changes to state law, including requiring domestic partners of public officials to submit financial disclosure forms, just as the spouses of heterosexual officials do.

It also would give domestic partners the same spousal testimony rights that married couples have, allowing domestic partners the right to refuse to testify against each other in court.

Opponents argued that expanding the current law brings the state closer to allowing same-sex marriage.

“This bill provides most of the rights of marriage,” said Sen. Dan Swecker, R-Rochester. “It would take little to achieve gay marriage other than simply a name change.”

Lawmakers rejected two amendments, including one that would have required the measure to be approved by voters.

Under the measure, the process of ending a domestic partnership also would be changed, allowing the secretary of state to end partnerships only in the first five years, with several more restrictions relating to children, real property or unpaid debts.

All other partnerships would be dissolved in superior court – similar to conventional divorce.

To be registered as partners, couples must share a home, must not be married or in a domestic relationship with someone else, and be at least 18.

In a provision similar to California law, unmarried heterosexual senior couples also are eligible for domestic partnerships if one partner is at least 62. Lawmakers said that provision was included to help seniors who are at risk of losing pension rights and Social Security benefits if they remarry.

The domestic partnership bill is House Bill 3104.