By Linda Sieg
TOKYO (Reuters) - Japanese Prime Minister Shinzo Abe's coalition was set on Thursday to approve legislation in the lower house of parliament that could see troops sent to fight abroad for the first time since World War Two, despite thousands of protesters overnight chanting and holding up placards reading "No War, No Killing".
A lower house panel approval on Wednesday of the unpopular bills, which would drop a ban on collective self-defense or fighting to defend a friendly country like the United States, sparked a huge demonstration and more are planned.
The protest was reminiscent of those that toppled Abe's grandfather from the premiership 55 years ago after he rammed a revised U.S.-Japan security pact through parliament.
Crowds of protesters - organizers said 100,000 - gathered near parliament. Many stayed well into the night, chanting and holding up placards reading "Abe, quit", "No War, No Killing" and "Scrap the War Bills".
Passage of the bills by the full lower house is virtually assured given the ruling bloc's big majority, although opposition parties were expected to boycott the vote.
The bills will then go to the upper house, and if no vote is taken after 60 days they will be returned to the lower house, where Abe's coalition can enact them with a two-thirds majority.
Abe says a bolder security stance, welcomed by ally Washington, is essential to meet new challenges, such as those from a rising China.
Opponents say the revisions could entangle Japan in U.S.-led conflicts around the globe and violate pacifist Article Nine of the U.S-drafted, post-war constitution.
Abe, who returned to office in 2012 pledging to bolster Japan's defenses and reboot the economy, has seen his support slip to around 40 percent on voter doubts about the legislation.
Some analysts have begun to draw parallels to Abe's grandfather, Nobusuke Kishi, a wartime cabinet minister who was premier from 1957 to 1960 and resigned on July 15, 1960 because of a public furor over the U.S.-Japan security pact.
Other analysts say that although Abe's ratings will take a hit, he is likely to survive and win re-election in September for another three-year term as leader of his Liberal Democratic Party, given weak opposition inside and outside of the party.
The changes, reflected in new U.S.-Japan defense cooperation guidelines, would also expand the scope for Japan's military to provide logistics support to friendly countries, relax limits on peace-keeping operations and make it easier to respond to "grey zone" incidents falling short of war.
(Editing by Michael Perry)