Tokyo ? When the opposition Democrats made strong gains in parliamentary elections in 2003 and 2004, Japan looked on the verge of something new: a competitive two-party system.

But the ruling coalition’s landslide victory in lower house elections on Sunday has dealt a major setback to such hopes, putting the Liberal Democratic Party firmly in charge.

The LDP, which has run Japan for nearly all the past 50 years, stormed to victory Sunday, boosting its standing in the lower house by nearly 50 seats in the 480-member chamber, to 296.

That success came at the painful expense of the opposition Democratic Party of Japan, which saw its standing plummet from 175 seats to 113.

The results were a shock to the Democrats. A grim-looking party leader Katsuya Okada stepped down to take responsibility for the defeat, and a meeting was scheduled for Saturday to choose a new party president.

The development puts Japanese politics at a crossroads of sorts.

With the ruling party at least temporarily unified under Koizumi, some say Japan could use a strong opposition more than ever before.

“The checks and balances that a democracy needs were provided by the (LDP) party itself,” Gerald Curtis, a Japanese politics expert at Columbia University, told reporters in Tokyo on Monday.

“That dynamic is gone, it’s over, so where do the checks and balances come from? It’s got to come from the opposition party,” he said.

But Curtis and others aren’t writing off the chance of a two-party system in Japan’s future.