“There are still many legally married, same-sex couples seeking Social Security benefits who continue to be viewed as second-class citizens in the eyes of the law,” said Senator Patty Murray, a Democrat from Washington, who co-sponsored a bill that would extend the benefits to all gay married couples, regardless of where they lived.

In fact, even for same-sex couples living in states where same-sex marriage is legal, “Social Security has been a hard ship to navigate,” said Gary Buseck, legal director at Gay and Lesbian Advocates and Defenders.

But when it comes to requests for all types of benefits, including pension benefits from a spouse’s employer, he said “a majority of folks are finding favorable results — but after a lot of persistent effort,” including contacting organizations like his own. “I worry about people who try once, face a mysterious negative response from an agency and then give up,” he added.

Some people have complicated questions, such as whether they are entitled to their late spouse’s pension benefits and whether they can collect those payments retroactively — as if the Defense of Marriage Act never existed. (For federal employees, the answer is generally yes. For private employees, it depends.)

The Employee Retirement Income Security Act — the federal law known as Erisa that governs many retirement and health plans — requires employer-provided pensions to follow certain rules that protect surviving spouses. For instance, married retirees must generally take their pensions in the form of annuities that provide payments to a surviving spouse, unless the spouses gives up that right. And if a worker dies before beginning to collect the pension, the spouse typically is entitled to half the pension payments the worker would have received.

“Every private sector company in America that has a pension is subject to these rules,” said Todd A. Solomon, a partner in the employee benefits department of McDermott Will & Emery, a law firm in Chicago.

The Internal Revenue Service, which also oversees pensions, does not require pension plans to provide retroactive benefits to survivors (at least before the Windsor ruling). But that does not mean workers cannot seek benefits; plans that did not clearly define the word “spouse” can be vulnerable to claims and lawsuits, he said.