WASHINGTON >> History will be trailing Japanese Prime Minister Shinzo Abe during his visit to the United States.

Abe intends to promote a free trade pact and stronger defense ties as his government loosens the shackles of Japan’s pacifist constitution 70 decades after the end of World War II.

But while Japan wants to look to the future, it cannot seem to shake off its past.

Korean-Americans who have championed the cause of former sex slaves of the imperial Japanese military will be watching what Abe says during his trip this coming week. So, too, will the shrinking ranks of American veterans who were prisoners of war.

In an unusual step, 25 House members wrote Japan’s ambassador to the U.S. to urge Abe to address sensitive issues of history when he becomes the first Japanese leader to address a joint meeting of Congress. Abe’s speech Wednesday comes a day after his scheduled meeting with President Barack Obama.

"To ignore past atrocities," said Rep. Steve Israel, D-N.Y., "is to ensure a very troubling future."

Since the 1990s, Japanese governments have apologized directly for wartime aggression and treatment of tens of thousands of women across Asia, many of them Koreans, who were forced to provide sex to Japan’s front-line soldiers.

Abe says his government upholds those apologies, and he has spoken of his "heartfelt sympathy" for those "comfort women." But he appears reluctant to repeat another apology himself, despite the complications that has caused in Tokyo’s attempts to improve relations with China and South Korea.

Abe’s hawkish reputation has made him a target of criticism in neighboring countries, but he did little to help matters when he visited a Tokyo shrine in December 2013 where war criminals, including wartime Prime Minister Hideki Tojo, are among those memorialized.

His speech to Congress will be watched for signs of how he might phrase a formal statement in August marking the war anniversary.

Japanese Ambassador Kenichiro Sasae said Abe will focus on the current and future challenges in the U.S.-Japan relationship, including the Trans-Pacific Partnership trade deal and mutual defense guidelines.

Abe’s Cabinet has reinterpreted an article of its pacifist constitution and is pushing security legislation that, if approved by Japan’s parliament, would allow Japan in some circumstances to defend U.S. forces if they were to come under attack.

Sasae said he expects Abe will speak about World War II, but added that Congress is not the right place to talk about other countries’ concerns over history.

A survey published this month by the Pew Research Center showed that despite the war and the fierce economic competition between the U.S. and Japan in the 1980s and early 1990s, 68 percent of Americans now trust Japan a great deal, although there’s less support for Japan playing a more active military role in the Asia-Pacific.

The U.S. has tens of thousands of troops based in Japan and South Korea, and treaty commitments that could see it drawn into any Japan-China conflict, so it has a stake in how Tokyo gets on with its neighbors.

The U.S. also has a vocal Korean-American population, mostly first- or second-generation immigrants, who are using their political muscle to highlight their concerns, particularly about comfort women.

One of the 53 Korean comfort woman survivors, Lee Yong-soo, 87, told reporters Thursday on Capitol Hill that Abe was "denying the truth."

She said at age 16, she had been taken from her home in Korea and shipped to Taiwan and forced to serve Japanese soldiers, who beat her and used electric shocks on her when she resisted. She said the two years of servitude had "destroyed her life." She demanded Abe make an official apology.

U.S. veterans of World War II also have grievances. Japan’s government has apologized to former American POWs, and in recent years has paid for "friendship visits" to Japan for survivors, giving them a more positive view of the country.

Instrumental in the friendship visits has been Lester Tenney, 94, who is among the 200 guests invited for a dinner Abe will host in Washington. Tenney said he wants an apology from Japanese industrial corporations that exploited U.S. prisoners of war like him as slave laborers.

Another former POW, Darrell Stark, 93, is worried that some in Japan are trying to rewrite wartime history.

"I have no hatred for Japan, although they treated me like an animal, and I have no problem with today’s Japanese people for what happened 70 years ago," said Stark. "But I do object to Japanese people not telling history the way it was."