PRESIDENT OBAMA has attached the District’s “Taxation Without Representation” license plate to his limousine. That is a good sign. He said he will display the plate for his full second term. That’s a good sign, too.

Or is it? Should we be pleased that the president assumes that there will be no changing, over the next four years, the injustice whereby residents of the nation’s capital must pay taxes while being denied representation in Congress? It’s good that Mr. Obama has taken notice of the issue. It would be even better if he would apply some muscle to the cause, demonstrating the “commitment to the principle of full representation” and the “willingness to fight” touted in a recent White House statement.

Not only are the 630,000 residents of the District denied a vote in the House and Senate but their elected city government lacks authority — enjoyed by every other local jurisdiction in the country — over its budget. Del. Eleanor Holmes Norton (D-D.C.) has introduced bills to give the District its rightful voice in Congress and its elected officials the freedom to spend local taxpayer dollars. Her efforts could stand a boost from the president.

The State of the Union address, set for delivery on Feb. 12, offers Mr. Obama an opportunity to take the next step in seeking full citizenship for District residents. By including a few words about the District’s plight, he would follow the precedent of other presidents, Republican and Democrat, who used their annual address to Congress as a call to action for equal treatment. “We should take adequate steps to assure that citizens of the United States are not denied their franchise merely because they reside at the nation’s capital,” President Harry Truman said in 1946. Dwight Eisenhower focused in a succession of State of the Union speeches on the lack of self-government and the denial of national suffrage: “In the District of Columbia, the time is long overdue,” he said in 1954. Lyndon Johnson and Jimmy Carter gave similar voice to District issues of their day.

The District secured home rule and the right to vote for president but — because of the hostility or timidity of national leaders — D.C. residents still lack basic political rights that other American citizens enjoy. In his upcoming address, Mr. Obama could explain to Americans why this is unacceptable — and signal his intention to do something about it during his second term.