Supporters of D.C. statehood call for an end to “taxation without representation” as they protest outside the U.S. Capitol on April 15. (Jim Lo Scalzo/EPA)

D.C. Mayor Muriel E. Bowser won an early endorsement Thursday of her ambitious plan to petition Congress and the next president for full statehood for the nation’s capital.

A commission that includes D.C. Council Chairman Phil Mendelson unanimously backed her proposal, including calling a constitutional convention to ready a statehood ballot initiative to put before voters in November.

Doing so could require the D.C. Council to convene in summer session and possibly delay action on other priorities. But Mendelson said Bowser had made a convincing case that the District cannot repeat the mistake of being flat-footed when the next president and Congress is elected — especially if Democrats who empathize with the District’s lack of voting rights win control of the White House, Congress or both.

D.C. now has more residents than either Vermont or Wyoming, and its residents pay the highest federal taxes per capita, but the District has no voting representation in Congress and federal lawmakers can dictate how the city spends its own local tax money.

“We could take more time, and taking more time would mean we miss what I think is going to turn out to be a historic election in November,” said Bowser (D). “We miss the opportunity for a new president to have a complete package from the voters of the District of Columbia.”

Mendelson added: “Given how Congress has viewed our effort, I don’t know that we can ask too often ... or demand too often that residents of the District be fully franchised.” However, the council chairman would not commit to finishing a constitution before November. “Let’s see if we can do it,” he said, and if not, he added, voters could pass an advisory measure and the city could continue working toward a vote on a constitution next year. “The main thing here is we want to present a fresh request [for statehood] and we will.”

The comments of both Bowser and Mendelson reflected the fact that crafting a new constitution could become a messy process, and completing the document on the mayor’s proposed timeline will be no easy task.

The last time the District drafted a constitution for statehood, the exercise in the early 1980s took more than two years and left District leaders bitterly divided over the end product.

At Bowser’s request, the New Columbia Statehood Commission also approved setting up a series of working groups and committees, including one launching a 50-state outreach program, another to finalize new boundaries for the would-be state and others to lobby businesses as well as politicians at the presidential conventions over the summer.

The District’s shadow senator, Paul Strauss, said he was already working on a plan for the conventions, including the Republican convention.

“We know that when we talk to Republicans there are themes that resonate,” Strauss said. “One is, nobody wants to be the subject of a dysfunctional Congress.”

The commission’s vote came as The Washington Post released the transcript of an interview with Republican presidential hopeful John Kasich in which he largely dismissed the need for D.C. statehood.

“That’s just more votes in the Democratic Party,” said the Ohio governor.

Strauss said he thanked the governor for his honesty. “It helps us make our case,” he said.