With his second three-year term as president of the ruling Liberal Democratic Party expiring in Sept 2018, Japan's Prime Minister Shinzo Abe has set himself the goal of revising the country's Constitution in the next two and a half years.

Abe unveiled his intention at the House of Councilors Budget Committee on Wednesday, although he was reticent about how he planned to rewrite the Constitution.

Following Japan's unconditional surrender to the Allied powers, the Japanese government introduced the so-called peace Constitution that eliminates a standing army and renounces war.

If Japanese public opinion has generally embraced Japan's status as a peaceful nation, conservatives and nationalists led by Abe have repeatedly attempted to revise the country's Constitution, which they consider a foreign imposition on Japan.

Above all else, Abe and other members of his party believe that Japan cannot fully regain its sovereignty until it has effectively changed the current Constitution.

But Abe is also seeking to revise Japan's Constitution by late 2018 to remove the constraints on his defense policies.

The House of Councilors election in July will be a golden, and possibly last, opportunity for Abe to give it a try, since half of the upper house's berths are up for grabs.

Constitutional amendment needs the approval of two-thirds of each house of parliament and a majority of voters in a national referendum.

During Abe's first term as prime minister in 2006 to 2007, he prepared the ground for this by passing a law on how to hold a national referendum when amending the Constitution. This set in place an essential steppingstone for eventual revision.

The coalition of the LDP and its junior partner Komeito already has a two-thirds majority in the lower house. But the LDP is having trouble mustering the required two-thirds majority in the upper house, and it is trying to form broad partnerships with any pro-amendment political allies.

And revising the Constitution was part of the LDP's election platform in December 2013.

The draft of constitutional amendments the LDP has released call for wide-ranging revisions to the Constitution, such as an extensive list of obligations borne by citizens and new emergency powers for the prime minister. And call for having constitutional review panels in both houses of parliament to first determine the items to be revised, and then compile a draft of the revisions for inter-party talks in 2016. The proposed revisions would then be passed in a regular session of parliament in 2017.

This is the LDP's fastest time frame for revising the Constitution.

In fact the Abe administration has already stretched the pacifist Constitution with a dramatic shift in security policy that ends a ban on Japan's military fighting overseas. It ramps up military spending and builds defense cooperation worldwide, with nations in Southeast Asia in particular.

Japan decided in 2013 to provide 10 patrol boats to the Philippines through its official development assistance program. The first vessel is to be handed over this summer.

Meanwhile, two Japanese Maritime Self-Defense Force destroyers accompanied by a submarine will anchor at Subic Bay in April. The last time an MSDF submarine went to the Philippines was 15 years ago. Analysts in Japan said the convoy is being "dressed up as purely a goodwill mission and an expression of friendship, but the real focus is China".

Abe's desire to press on with constitutional revision before the July poll suggests that he feels his chances of securing a two-thirds majority in the upper house are uncertain.

He risks squandering support in pursuit of the project that has already unnerved many Japanese people.

The author is China Daily Tokyo bureau chief. caihong@chinadaily.com.cn