Prime Minister Shinzo Abe is facing a major challenge ahead of his summit with U.S. President Barack Obama later this month, as calls have mounted within the ruling Liberal Democratic Party for Japan not to participate in U.S.-led free-trade talks.

Abe, who heads the LDP, and his aides at the prime minister’s office apparently want the country to join in the Trans-Pacific Partnership talks, which hold both the promise of opening up more foreign markets for Japanese exporters and the threat of dealing a serious — if not critical — blow to the agricultural sector, in particular rice and cattle.

But apparently most Diet members from the LDP, which has long depended on the rural vote, oppose Japan joining the ongoing TPP talks. The farm sector, including the long-subsidized rice growers, is both a major source of votes and funds for the party, and an Upper House election looms large this July.

An anti-TPP meeting is slated for Wednesday involving more than 200 of the LDP’s 376 Diet members from both chambers, including Cabinet ministers.

“The number (of opponents to the TPP) is increasing. We will release a new list of members soon,” an LDP source said last week.

Since the Lower House election campaign in December, Abe has stressed that his diplomatic strategy will center on boosting Japan’s ties, in terms of both the security treaty and economic matters, with the United States, particularly as a way to keep an ever-intrusive China and other rival countries in check.

The U.S. meanwhile wants Japan to further open its market for beef, insurance and automobiles, and sees the TPP process as key to these goals.

“I think (Abe) feels he must show a positive attitude toward the TPP” to win the Obama administration’s trust, a senior government official said on condition of anonymity.

“(But) the TPP issue is really difficult,” the official said, suggesting many LDP Upper House members running for re-election this summer fear facing a rural voter backlash if Japan joins the talks.

The first Abe-Obama meeting is expected to take place Feb. 21 or 22 in Washington.

At present, 11 nations, including the United States, Canada, Australia, Mexico, Singapore, New Zealand and Peru, are engaged in the TPP negotiations to conclude a comprehensive free-trade agreement that would theoretically leave no sectors protected.

The negotiations assume all trade issues will be placed on the bargaining table, and so far no sensitive items have been excluded.

The dilemma: Japan’s export sector worries that a failure to get in on the ground floor of a TPP trade accord will put Japanese companies at a disadvantage and jeopardize the global competitiveness of many firms, but farmers fear that joining the TPP would decimate them if all tariffs are removed, particularly those protecting rice, pork, beef and dairy products.

“The domestic agricultural industry will suffer devastating damage, and it would threaten the survival of not only domestic farm production but also entire rural communities,” Hokkaido Gov. Harumi Takahashi said in a written statement.

During the recent election, the LDP pledged not to join the TPP talks as long as the participants uphold the general rule that no tariff sanctuaries will be allowed. Thus Abe has had to avoid for now any political gesture taken as a commitment to join the talks.

As can be expected, the various ministries are also divided over the TPP.

The farm ministry claims that joining would slash the nation’s agricultural production to the tune of ¥4.1 trillion, push down gross domestic product by ¥7.9 trillion and eliminate 3.4 million jobs.

Of the ¥4.1 trillion loss, rice output would be hit the hardest — 48 percent of the total — followed by pork, beef and dairy products at 11 percent each, according to the estimate by the agriculture ministry.

But the trade and industry ministry argues that if Japan fails to enter the free-trade regime, GDP would suffer a 1.53 percent drop and 812,000 jobs would be lost.

“It doesn’t make sense that the government has two estimates that contradict each other,” a senior official said.

Akira Amari, the economic revitalization minister and a close aide to Abe, told reporters Sunday the government will soon compile a unified estimate regarding the impact of the TPP.

“We should prepare (for Abe’s visit to the U.S.) so that the prime minister can pledge to come up with the unified estimate” during his talks with Obama, Amari said.

Obama is someone who prefers substantive talks that result in concrete achievements, instead of political ceremony just to demonstrate friendship during a summit. But without progress on the TPP position, Abe may find himself diplomatically hard-pressed to demonstrate how he will strengthen Japan’s alliance with the U.S.

To show that the bilateral security alliance is strong, Abe also reportedly hopes to stress his plans to change the government’s interpretation of the Constitution, in order to allow Japan to exercise the right of collective self-defense with America in the event of a military emergency.

But Washington reportedly told Tokyo it does not want Abe to bring up the issue of collective self-defense at the upcoming talks, fearing Beijing might believe the U.S. is trying to put more pressure on China.

Tokyo will now need to quickly find another way of showing the rest of the world that the Japan-U.S. alliance is strengthening, Kyodo News quoted government sources as saying.

The Constitution has long been interpreted to prohibit Japan from using the right of collective self-defense as recognized under the United Nations Charter, and it has been considered a key obstacle for Japan to provide more direct support for U.S. military operations.

The hawkish Abe has long called for a change in the government’s interpretation of the Constitution, in order to strengthen the Japan-U.S. military alliance.