Japan set the cogs in motion for the ratification of the 12-nation Trans- Pacific Partnership (TPP) trade treaty, with the Bill clearing its first hurdle at a special parliamentary committee on Friday.
The treaty is now expected to be approved at a Lower House plenary session on Tuesday, hours before the United States goes to the polls to pick its next president.
After Tuesday's plenary session, the Bill will automatically clear the Diet after 30 days even without the backing of the less powerful Upper House. The ruling coalition led by the Liberal Democratic Party (LDP) holds a supermajority in both houses of the Diet.
Prime Minister Shinzo Abe's conservative government has urged the fast ratification of the pact as a signal to the US that the reopening of talks was not on the table.
LDP lawmaker Tomohiro Yamamoto said on Friday that Japan's ratification "will send a clear signal to the US that Japan has no intention of renegotiating the agreement".
The beleaguered treaty was once seen as a linchpin of US presence in Asia, but has run into opposition in the US Congress. The candidates of the US presidential election, Democrat Hillary Clinton and Republican Donald Trump, also oppose the TPP in its current form.
But in a sign of how volatile the TPP issue has become even in Japan, the Japanese Diet descended into a fracas after Friday's vote as some opposition lawmakers lodged protests while others staged a walkout. There were scuffles and shoving, as some opposition lawmakers brandished signs that read "No steamroll vote!" and "We're against the TPP!".
Opposition lawmakers have accused the ruling coalition of bulldozing the Bill through Parliament without adequate debate.
The main opposition Democratic Party's policy research chief Hiroshi Ogushi said: "The TPP agreement is a 6,000-page document. There are many issues to be looked at... There is no need for Japan to ratify the agreement before everyone else."
The 12 nations in the TPP - including the US and Japan but not China - account for a combined 40 per cent of the global economy.
Japan has touted it as being vital towards creating an estimated 800,000 jobs and an annual growth of 2.5 per cent, giving a shot in the arm to its stagnant economy.
The vote in the Lower House special committee was scheduled to be held last Wednesday, but was delayed after agriculture minister Yuji Yamamoto committed a string of gaffes. He said last month that the ruling LDP wields the power to "railroad Bills" related to the TPP, which he later said was "a joke". At another event, he suggested he could peddle influence for agricultural operatives.
Japanese centre-left daily Asahi Shimbun said in a scathing editorial yesterday that the brief debate on the TPP failed to address myriad issues such as food safety.
"The legislation for the TPP pact covers a wide range of issues with significant implications for people's livelihoods. That's exactly why thorough debate is needed for the Bills," it said.