TOKYO — Japan’s voters handed a landslide victory to the Liberal Democratic Party in national parliamentary elections on Sunday, giving power back to the conservative party that had governed Japan for decades until a historic defeat three years ago.

In a chaotic election crowded with new parties making sweeping promises, from abolishing nuclear power after the Fukushima accident to creating an American-style federal system, the Liberal Democrats prevailed with their less radical vision of reviving the recession-bound economy and standing up to China. A victory would all but ensure that the Liberal Democratic leader, Shinzo Abe, a former prime minister who is one Japan’s most outspoken nationalists, would be able to form a new government.

Some here saw the victory pointing to a greater willingness by this long pacifist nation to accept Mr. Abe’s calls for a stronger military at a time when Japan faces an intensifying showdown with China over disputed islands.

However, the dominant view of Sunday’s vote was that it was not so much a weakening of Japan’s desire for drastic change, or a swing to an anti-Chinese right, as a rebuke of the incumbent Democrats. They swept aside the Liberal Democrats with bold vows to overhaul Japan’s sclerotic postwar order, only to disappoint voters by failing to deliver on economic improvements. Mr. Abe acknowledged as much, saying that his party had simply ridden a wave of public disgust in the failures of his opponents.