(Repeats story first sent on Monday, no change to text)
* Abe coalition allies resist reinterpreting constitution
* Internal opposition could delay, water down changes to military role
* Abe chafes at limits on military helping allies abroad
By Linda Sieg
TOKYO, March 24 (Reuters) - Prime Minister Shinzo Abe is hitting a speed bump in his drive to ease constitutional limits on Japan's ability to fight abroad, as members of his own coalition put up obstacles that could force him to delay or water down the move.
Abe has made clear he will press on with changes to free the military from the constraints of the pacifist constitution, but members of his own party are urging caution and his coalition partner is dubious about the wisdom of the historic - and unpopular - change.
Allowing the Self-Defense Forces to aid the United States or other allies under attack would mark a turning point for Japan's military, which has not fired a shot in conflict since World War Two. It would increase the chances of involvement in wars overseas - and almost certainly strain already fraught ties with neighbours China and South Korea.
After parliament last week enacted Abe's budget for the coming fiscal year, so-called collective self-defence looks set to dominate the remaining three months of this session.
Other aspects of Abe's agenda, which seeks a more muscular military and a less-apologetic foreign policy, have also run into trouble. His December visit to Tokyo's Yasukuni Shrine, seen by critics as a symbol of Japan's wartime militarism, upset not only Asian neighbours China and South Korea but security ally the United States, which expressed "disappointment".
Abe has had to back away from any attempt to revise a 1993 government statement apologising for government involvement in forcing Asian women to serve as prostitutes for Japanese soldiers in World War Two under U.S. pressure to repair frayed ties with Washington's other key Asian ally Seoul.
The government is not making a direct assault on the constitution to allow collective self-defence, but instead aims to reinterpret the charter to authorise the use of force to help allies abroad. But even some of Abe's political allies are wary of that approach.
"I think it is wanton for the government to change overnight the interpretation of the constitution to allow the exercise of the right of collective self-defence," Natsuo Yamaguchi, leader of dovish coalition partner New Komeito, said over the weekend in one of his strongest statements on the topic.
Given such obstacles, Abe now "realises that it is not so easy as he expected two or three months ago", said Hokkaido University Professor Jiro Yamaguchi, a member of a group of about 30 academics opposing the change. "It will take longer."
The need to compromise, especially with the New Komeito but also with less hawkish members of Abe's conservative Liberal Democratic Party, could limit the scope of eventual changes.
Abe says there is no deadline to decide. But failure to adopt a cabinet resolution and seek needed legal changes in an autumn session of parliament would make the new interpretation too late to include in an upgrade of U.S.-Japan defence cooperation guidelines, which the allies want to complete by the end of the year.
The push-back from the New Komeito could force Abe to whittle down the scope of reinterpretation, perhaps to allow aid only for the United States and only in conflicts close to Japan.
Abe chafes at Article 9 of the constitution, in which "the Japanese people forever renounce war" and the "threat or use of force as a means of settling international disputes". Japan also gives up the right to maintain land, sea and air forces, as well as other "war potential".
Conservatives argue the charter was imposed by the United States on a defeated Japan and should be rewritten, although it has long been stretched to allow armed forces purely for self-defence. Japan's military is on a par with that of France.
But formal amendments must be approved by two-thirds of both houses of parliament and a majority of voters, a hurdle lawmakers have never attempted to clear since the constitution took effect in 1947.
Abe and his advisers say security tensions, including China's growing military clout and an unpredictable North Korea, mean Japan can't wait.
Critics counter that lifting the ban through a simple cabinet resolution for example would undermine the foundations of the constitution, making a mockery of amendment procedures. A weekend poll by Kyodo News found that 58 percent of the public oppose revising the interpretation while 34 percent support the change.
Some see a disturbing echo of Adolf Hitler evading Germany's constitution by passing a law that gave the cabinet the power to decree legislation.
"If this is achieved, any cabinet could change the interpretation of the constitution by adopting a resolution and passing laws," said Seiichiro Murakami, a veteran lawmaker and a rare outspoken critic of the prime minister in Abe's party.
"In the same way that the Nazis passed a law and twisted the Weimar Constitution, there is a danger that Japan could again tread a mistaken path," Murakami told Reuters.
Deputy Prime Minister Taro Aso sparked outrage in July by appearing to suggest the government do just that.
The Nazis changed the constitution "before anyone was aware", he said. "Why don't we learn from that technique?" Aso later retracted the widely vilified remarks, saying he had caused misunderstanding.
Abe's advisers have been planning to issue a report next month recommending a reinterpretation of Article 9 to allow collective self-defence. Abe appointed an ex-diplomat who shares his views to head the government's constitutional watchdog, the Cabinet Legislation Bureau.
The prime minister then plans to discuss the proposal with the ruling parties, adopt a cabinet resolution and submit necessary revisions to current laws to parliament.
But the New Komeito is resisting the timeline.
"This notion of the prime minister lacks the most critical element of listening to the voice of the people, and I can by no means agree," wrote New Komeito executive Yoshio Urushibara on his website late last month.
Potentially more troubling for Abe are calls from his own party for more debate.
Few would risk a frontal attack on Abe as long as he remains popular, the LDP's Murakami said. The premier's ratings are above 50 percent, high for a Japanese leader, buoyed mainly by hopes for his "Abenomics" recipe for fixing the economy.
But Murakami said that internal party dynamic could change as time goes by, making it harder to revise the interpretation of the constitution.
Yukio Edano, a former top government official who heads the opposition Democratic Party's panel on constitutional matters, predicted Abe's government "will find ways, without changing the overall interpretation, to explain that some things that were previously not possible are possible under the constitution".
Even a limited reinterpretation, critics say, could give the government a foot in the door to make broader changes later.
"It is a very simple truth, and as scholars and political scientists, we should keep saying that Abe's project is a challenge to the constitutional system," said Hokkaido University's Yamaguchi. (Additional reporting by Nobuhiro Kubo; Editing by William Mallard and Dean Yates)