“I WON’T PRETEND the path I’m offering is quick or easy,” President Obama said Thursday night in accepting the Democratic nomination for a second term. “I never have. You didn’t elect me to tell you what you wanted to hear. You elected me to tell you the truth.”

But as with Republicans in Tampa a week ago, the content of Mr. Obama’s remarks was short on those hard truths.

Addressing his party’s convention in Charlotte, Mr. Obama acknowledged problems that Republican nominee Mitt Romney ignored or dismissed in his own acceptance speech, such as the impact of global warming. He offered more specific goals than did Mr. Romney, many of which he had previously set: doubling U.S. exports, training 2 million workers at community colleges, recruiting 100,000 math and science teachers. Those, and a few new goals — creating 1 million manufacturing jobs over four years, cutting oil imports in half by 2020, cutting in half the growth in college tuition — are laudable. But Mr. Obama did not explain how he would achieve them or prepare the country for the difficult choices they would demand.

An acceptance speech is not a State of the Union laundry list of specific proposals. Its role is to set out a vision of the country’s future path. Mr. Obama was correct that he and Mr. Romney have dramatically different visions of government’s role, and that the Republican prescription of tax cuts to address any woe has left the country in terrible shape. Mr. Romney has been inexcusably vague in outlining his program, fiscal and otherwise, and he did nothing to mend this deficiency in his acceptance speech. But Mr. Obama’s speech also fell short — of his own proclaimed standards.

He vowed, “I will never turn Medicare into a voucher,” but he gave his audience no indication that his solution — controlling health care costs — might involve sacrifice on the part of seniors. He promised “responsible steps to strengthen” Social Security, which he has neglected throughout his first term. As to which steps those might be, not a word. “My plan will continue to reduce the carbon pollution that is heating our planet,” Mr. Obama said. What plan would that be?

Mr. Obama sketched a tempting array of expensive benefits and changes: eliminating overcrowded classrooms and crumbling schools; preserving the strongest military in the world; making certain that children can afford college. But he did not offer a whiff of explanation of how those programs can be paid for and the mounting national debt brought under control. Mr. Obama proferred his old plan to cut the debt by $4 trillion over the next decade, but that number includes $1 trillion in spending cuts already agreed to and nearly $900 billion in imaginary savings from winding down the wars in Iraq and Afghanistan.

Mr. Obama boasted of foreign-policy achievements and challenged his opponent’s views and credentials in that area. Some of his boasts were justified, others less so; it had to be galling for Syrians to hear him present himself as a champion of “the rights and dignity of all human beings” without mentioning their country, where civilians are slaughtered by the thousands while the United States stands by. As with his domestic promises, he offered no new vision for challenges that have resisted his first-term efforts, such as Iran’s march toward acquiring a nuclear weapon.

The president offered an appealing, even a stirring, vision of a shared citizenship and commitment to democracy. “We don’t think government can solve all our problems,” he said. “But we don’t think government is the source of all our problems — any more than are welfare recipients, or corporations, or unions, or immigrants, or gays, or any other group we’re told to blame for our troubles.”

But the attractiveness of that vision made all the more frustrating Mr. Obama’s refusal to fill in any substance, his once again promising hard truths that he did not deliver. “They want your vote, but they don’t want you to know their plan,” he said of the Republicans. If Mr. Obama has a plan, Americans who listened Thursday don’t know how he would achieve it.