TAHARA, Japan — Just two months into office, Prime Minister Shinzo Abe is showing an increasing willingness to take on some pillars of Japan’s establishment — the central bank and the country’s politically influential farmers — in an aggressive attempt to finally breathe some new life into Japan’s listless economy.

Mr. Abe has already forced the departure of the cautious head of the central Bank of Japan and nominated a replacement who vowed Monday to do “whatever it takes” to fight crippling deflation that has eroded profits and wages and stifled spending. Mr. Abe is also expected to announce soon that his nation will join negotiations on an American-led Pacific free-trade pact that the Obama administration hopes will offset China’s growing economic and political might, but that could also force Japan to make painful, market-opening changes it has resisted for nearly two decades.

Joining the pact risks alienating farmers, longtime staunch supporters of Mr. Abe’s conservative Liberal Democratic Party, who would face more intense competition from cheaper imports.

But the broader public appears more willing to embrace drastic economic measures at a time when Japan, the region’s waning economic superpower, feels threatened by China, helping push Mr. Abe’s approval ratings to around 70 percent in recent polls. That is a vast improvement from his disastrous first term in office six years ago, and from concerns that his hawkish views might alienate him once again from voters.