The ruling coalition may give up trying to get the Trans-Pacific Partnership ratified during the current Diet session if resistance from opposition parties means it is delayed beyond the end of April, a senior ruling lawmaker said Wednesday.

In that case, deliberation on the agreement and related bills would be carried over to a Diet session in the fall. The current ordinary Diet session runs until June 1.

Meanwhile, Prime Minister Shinzo Abe has instructed the coalition not to “forcibly” proceed with the TPP deliberations, Kyodo News reported. He is thought to fear a voter backlash in the Upper House election this summer.

The potential postponement was announced by Tsutomu Sato, the Diet affairs chief of the ruling Liberal Democratic Party, speaking to reporters at the Diet. But he added, the LDP-Komeito coalition has not yet given up on seeking ratification by the end of the current Diet session.

Later Wednesday, the LDP and the Democratic Party, the largest opposition force, agreed to resume deliberations on the TPP deal and will convene a session of the Lower House TPP special committee on Friday.

Still, frustration remains palpable among many lawmakers.

The records of TPP negotiations, released by the government in response to opposition demands, were largely blacked out, ostensibly to protect secret parts of the multinational trade negotiations.

This has given ammunition to opposition parties. They have been lambasting the government and boycotted all deliberations at the Lower House on Wednesday.

LDP lawmaker Koya Nishikawa, the chairman of the special committee on TPP, is now a major target of the opposition parties.

The DP obtained what it says is a 242-page draft of a book being written by Nishikawa, in which he reveals details about the closed-door TPP negotiations that the government has not disclosed. Nishikawa is a former farm minister and is seen as maintaining influence over the government’s agricultural policies.

The DP has refused to attend any TPP sessions unless Nishikawa admits that the copy of his manuscript is genuine, because many of their questions on TPP would be based on its contents rather than the scant information released by the government.

Nishikawa has refused to authenticate the copy. But the signs are that it is genuine: In conversation with a government official during Friday’s Lower House session, Nishikawa appeared to say so.

The conversation was picked up by a microphone that Nishikawa had forgotten to switch off. The comment can be clearly heard in a video clip posted online by the secretariat of the Lower House.

“It is the oldest stuff, not the one I (rewrote) in an organized manner. The one I scribbled down,” Nishikawa is heard saying.

Abe’s top priority nowadays seems to be to secure a strong win in the Upper House election this summer. Analysts say he is doing everything he can to minimize political fallout that might weaken the LDP’s performance in the poll.

Last month, Abe announced a set of measures designed to help mothers with young children who cannot find places at nurseries.

Abe unveiled the measures shortly after a blog by an anonymous mother was widely cited on the Internet and secured media coverage. It reflected the long-running frustration of many women forced to abandon careers due to capacity shortages in the nation’s public child-care services.

Meanwhile, many right-leaning activists and politicians see the Upper House election as a rare chance to gain political momentum for a contentious goal: revising the pacifist Constitution.

Many such voters are the core supporters of Abe, the first prime minister who has openly called for revision of the postwar Constitution.