FOR ANYONE WHO hadn't been paying attention the past 31/2 years, President Bush's speech last night presented a robust defense of his first term and a forceful case for giving him a second. The president trumpeted some of his achievements at home and abroad and began to fill in the blank space of the campaign so far: what another four years of a Bush administration would bring. Compared with many of the speakers who preceded him, Mr. Bush dealt rather gently though still not entirely fairly with his opponent, Massachusetts Sen. John F. Kerry. He offered a stirring vision of spreading democracy in the Middle East and laid out an ambitious, if gauzy, set of goals, including reforming the tax code and building an "ownership society." The chief difficulty with Mr. Bush's speech wasn't so much what he put in, but what he left out: the missteps and difficulties that have marred his first term and will make many of the goals he cited difficult to obtain.

After three days of a convention that focused almost entirely on terrorism and national security, Mr. Bush devoted a significant part of his speech to domestic issues. "Many of our most fundamental systems -- the tax code, health coverage, pension plans, worker training -- were created for the world of yesterday, not tomorrow," Mr. Bush said. "We will transform these systems so that all citizens are equipped, prepared and thus truly free to make your own choices and pursue your own dreams."

While his diagnosis was apt, his proposals were short on detail. Mr. Bush proposed -- or re-proposed -- allowing Americans to shift a portion of their Social Security taxes into private accounts, a notion that was at the center of his campaign four years ago. But he didn't tell the audience that establishing such a system would cost $1 trillion or more over the next decade -- a cost that is even more daunting now that Mr. Bush's tax cuts have piled up record deficits. Indeed, while he did not mention the deficits, Mr. Bush promised to make his reckless tax cuts permanent. He railed against federal spending, but proposed a raft of new spending programs and tax credits.

When he turned to the United States in the world, Mr. Bush was even more impassioned, describing a nation promoting liberty throughout the globe. "The wisest use of American strength is to advance freedom," Mr. Bush said. "As the citizens of Afghanistan and Iraq seize the moment, their example will send a message of hope throughout a vital region." This vision contrasted sharply not only with Mr. Bush's far more modest foreign policy goals of four years ago but also with Mr. Kerry's increasingly cramped description of U.S. aims in Iraq and elsewhere. Where Mr. Kerry now speaks of ceding burdens and bringing troops home, Mr. Bush reiterated his commitment to elections, stability and democracy in Iraq and Afghanistan. He also acknowledged the human cost of some of his decisions in those wars and spoke movingly of witnessing the suffering of American families who have lost loved ones.

But as in his portrayal of domestic goals, Mr. Bush left many gaps. The war in Iraq has proven far more difficult and costly than he predicted; there was no acknowledgment of the surprises encountered. Surely the mission also faces agonizingly difficult moments ahead; Mr. Bush gave no indication of how he would navigate them. He proclaimed a profound commitment to confront and preempt the world's dangers, based on a worldview seared into him on Sept. 11. But he did not mention two of the gravest threats, the potential nuclear arsenals of Iran and North Korea, which have sharpened under Mr. Bush's watch.

With two months to go before Americans vote, both parties have now staged what they each deemed to be successful nominating conventions. The Democrats spent most of theirs introducing their candidate as a trustworthy commander in chief; the Republicans, until Mr. Bush's speech last night, to tearing their opponent down. Each candidate devoted most of his acceptance address to proving his credentials as a wartime leader, though for different reasons. Mr. Kerry hoped to demonstrate his plausibility and then change the subject to the economy, while Mr. Bush hoped to deflect attention from economic troubles and convince Americans that only he can be trusted in this time of peril. Whatever their intent, the effect has been to set the stage for the first campaign in many years to turn on national security. Given the hard choices a leader will face in the next term, that is appropriate.