Shinzo Abe, Japan's prime minister and president of the ruling Liberal Democratic Party, leaves a news conference at the party's headquarters in Tokyo on Monday. (Kiyoshi Ota/Bloomberg News)

Shinzo Abe has long held a dream — to redraw Japan’s pacifist constitution. And this week, after Japanese voters had given his coalition government yet another decisive election win, it seemed perhaps time to make it a reality.

“This is a new beginning,” Abe told reporters gathered at his official residence Monday morning. “We will implement policies, and we want to deliver results.” 

But only a few hours later, the prime minister cut a far less optimistic figure. In a news conference celebrating his victory, Abe dismissed a suggestion that he would set a deadline of 2020 to change the most controversial part of the constitution, Article 9, which renounces war and prohibits an army — suggesting instead that it was “not bound by any schedule.”

That cautious rhetoric is not what might be expected from a politician who is on track to become the longest-serving Japanese prime minister and has few, if any, serious rivals. Abe’s coalition government easily overcame opposition movements in Sunday’s election to retain its two-thirds majority in the lower house of Japan’s parliament.

However, the prime minister’s caution on constitutional changes is understandable. Abe has proved himself remarkably adept at maneuvering Japan’s parliamentary politics — and he probably knows that amending the constitution will require a high level of public support he may not possess.

Even allies are unsure that Japanese citizens can be convinced to amend Article 9. Former defense minister Shigeru Ishiba, a member of Abe’s Liberal Democratic Party (LDP) and a vocal proponent of rewriting the constitution, said in an interview that it had proved “extremely difficult” to mobilize citizens behind the issue.

In theory, the coalition government’s two-thirds majorities in both houses of parliament means it can push through pretty much any legislation it wants, including changes to Article 9. Abe would clearly have the parliamentary support: One analysis found that 80 percent of politicians in the newly elected lower house supported a rewrite of the constitution.

Any changes to the constitution, however, then require majority approval from the public in a referendum. Polls show mixed support for amending Article 9 among Japanese voters. And as the Brexit vote showed Britain’s David Cameron, winning an election is not the same thing as winning a referendum. 

“One thing that Mr. Abe does not want is to go out as a failure,” said Michael Cucek, an adjunct professor of politics at Temple University’s Japan campus in Tokyo. “Messing up the first attempt to ever amend the constitution would be extremely damaging.”

Abe is not the first politician who felt that Japan’s pacifist constitution needed revising. The document was adopted in 1947 while the country was under U.S. occupation. Seven years later, the LDP — the party Abe leads — was founded with the creation of a new constitution one of its objectives. 

The issue later picked up steam in the 1990s with the formation of the reformist group Nippon Kaigi, of which Abe is a member. However, it is largely thanks to the 63-year-old Abe that it has come to the forefront of Japanese politics. During his first term as prime minister in 2007, his ruling coalition pushed through the laws that outlined the referendum process that is now so daunting to him.

In 2014 and 2015, Abe’s coalition enacted legislation that reinterpreted the role of Japan’s Self-Defense Forces and allowed them to fight with allies overseas — a move that brought condemnation from opposition lawmakers, activists and neighboring nations such as South Korea and China.

Despite this controversy and other scandals, Abe’s coalition government has retained power. Earlier this year, on the 70th anniversary of the enforcement of the constitution, Abe said that he hoped to amend it within three years. A powerful victory should give him a larger window of time within which he could push for real constitutional change.

However, the coalition government’s enduring supermajority may have overshadowed another aspect of Sunday’s vote — the emergence of the Constitutional Democratic Party of Japan (CDPJ), which opposes any amendments to the constitution. That party, formed 20 days ahead of the election, became the second-largest party in parliament, beating the more-hyped (and pro-amendment) Party of Hope led by Yuriko Koike, the governor of Tokyo.

For some, the election felt like a partial victory for the anti-amendment movement. “We weren’t defeated,” said Mitsuhiro Hayashida, an anti-nuclear activist and student who worked with the CDPJ ahead of the election. “And the ruling parties don’t think it’s totally a victory.”

Abe may have another problem in his quest — his own government. While the LDP holds most of the seats in the coalition, it shares the government with its junior partner, Komeito.

Komeito’s base has long been skeptical of any amendment to the constitution, in part because of its links to the Buddhist group Soka Gakkai. In an apparent attempt to appease this group and others who oppose amending the constitution, Abe has proposed a compromise that would involve adding language to the constitution to clarify the legal standing of the Self-Defense Forces.

This attempt to add to the constitution rather than amend it brings its own enemies. The LDP’s Ishiba is among those who favor rewriting the constitution as a whole, rather than making a compromise. “We shouldn’t take the easy approach,” he said.

Andrew Oros, author of the recently published “Japan’s Security Renaissance,” suggests that Abe will choose to push forward with a constitutional referendum that focuses not only on Article 9 but also on less controversial aspects of the constitution.

“I predict that Abe will use the upcoming visit of U.S. President Trump as a time to talk about the need to revise the constitution to make Japan safer and will use momentum from the Trump visit to push that agenda forward,” he said.

But others have their doubts, and Abe’s personal support for constitutional changes could end up being a liability: Even though his party won handily, an exit poll this weekend showed 51 percent of voters said they did not trust the Japanese prime minister.