A federal judge in Eugene on Wednesday heard arguments in favor of striking down Oregon's ban on gay marriage.

The case is unique in that all parties represented, including the state, unanimously oppose the ban.

“We simply can't imagine a rationalization for the ban,” a lawyer for the state told U.S. District Judge Michael McShane.

Supporters of marriage equality held rallies in seven cities on the eve of the hearing.

“Every adult – every single adult – ought to be able to marry that person they love. It is time,” Senator Ron Wyden, a Democrat, told a crowd at one of the rallies held in downtown Portland. “If you don't share our view, if you don't approve of gay marriage, don't get one.”

In a last-minute filing, the National Organization for Marriage (NOM) asked to intervene in the case.

“The notion that there are no plausible arguments to make in defense of marriage is ludicrous,” said NOM Chairman John Eastman.

Jack Louman, executive director of Oregon Family Council, called the state's refusal to defend the ban “shameful.”

“We support any intervention to defend Oregon's marriage laws that were duly enacted by the people of Oregon. Everyone has had their voice heard in this case except the majority of Oregonians who voted to define marriage as between one man and one woman in 2004,” he said in a statement.

McShane will consider NOM's request during a May 14 hearing. He briefly touched on the request during Wednesday's hearing, saying that the case was unique because if he strikes down the ban, there will be no appeal.

(Related: Oregon judge denies attempt to delay arguments in gay marriage case.)

The Oregonian reported that a group of about 40 supporters who gathered to watch a streaming video feed of Wednesday's proceedings “liked what they heard.”

“A little bit of history is being made here today,” said Mike Marshall, campaign manager for Oregon United for Marriage.