Parliament in the officially pacifist nation passed the contentious security bills early yesterday, a move that could see Japanese troops engage in combat overseas for the first time since the end of World War II.
The legislation has sparked unprecedented angry street protests with tens of thousands taking part, prompted threats of a legal challenge, and fuelled anger among Japan's neighbours.
China and the two Koreas, which suffered harsh Japanese occupations in the 20th century, all blasted the new laws.
Abe sees them as necessary to protect against threats from China and North Korea, but opponents fear the vague wording could see Japan dragged into far-flung foreign conflicts similar to the US invasions of Iraq or Afghanistan.
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"After observing stronger than initially expected opposition, speculation is rising that the new laws are politically difficult to actually use," said Tomoaki Iwai, professor of politics at Nihon University.
"Public support for the Abe administration will decline, if temporarily, after enacting the bills amid doubt whether the legislation is unconstitutional."
Any lawsuit aimed at overturning the legislation could take years to wind its way through various lower courts before reaching the Supreme Court.
But Abe's ruling Liberal Democratic Party faces upper-house elections next summer. While a loss would not force a change of government, it would mark a significant blow to the 60-year-old leader and his party, underlining the political toll the new laws have taken.
"Abe's government could last long but his political capital will decline gradually," said Tetsuro Kato, professor emeritus at Hitotsubashi University, noting that the official opposition is weak and Abe has no meaningful rivals within his party.