When Prime Minister Shinzo Abe travels to the U.S. next month for a meeting with President Barack Obama, he will find new secretaries of state and defense.

Democratic Sen. John Kerry, nominated by Obama to replace Hillary Rodham Clinton as the top U.S. diplomat, is expected to easily win Senate confirmation after his hearing starts later this week. Former Republican Sen. Chuck Hagel, an Obama confidant, is the more controversial appointee as Pentagon chief. His confirmation hearing will be held late next week, but will be far more contentious than Kerry’s.

The direction Kerry and Hagel would set for the U.S.-Japan relationship is unclear.

But if past actions and comments by both men are any indication, they may want to emphasize issues that conservatives in Tokyo and Washington would prefer remain unmentioned, and that their stance toward China and North Korea could be less strict than many in Japan, especially around Abe, are comfortable with.

Both Kerry and Hagel have voiced support for a strong relationship with Japan, and Kerry has suggested Washington and Tokyo should seek out new areas of cooperation.

A longtime environmentalist, Kerry attended the 1997 United Nations meeting in Kyoto that forged the Kyoto Protocol. He sees global warming as a major international issue and may pressure Japan to do more to reduce greenhouse gases.

In addition, Kerry was one of 22 senators who signed a letter to Obama in 2009 urging pressure on Japan not only to sign the Hague Convention on international child abductions but also to establish a bilateral mechanism to resolve 79 cases involving more than 100 American children brought by estranged parents to Japan.

Abe will continue to seek Washington’s support for a tough stance toward North Korea. But he may find Kerry less sympathetic than Clinton. Kerry has criticized Obama’s handling of relations with Pyongyang.

“Our current approach of strong sanctions and intense coordination with South Korea and Japan does not provide sufficient leverage to stabilize the situation, much less bring about a change in North Korean behavior,” he wrote in a June 2011 opinion piece for the Los Angeles Times.

Like Kerry, Hagel attended the Kyoto Protocol conference, but he railed against it, saying it was meaningless without China’s participation. That gained him a reputation as being tough on Beijing. More recently, he has emphasized good relations with Beijing.

“The relationship between China and the United States is now as critical as any bilateral relationship, maybe in history and certainly in modern history. If we don’t build our relationship with China sturdily, mightily, right now, (then) whatever differences we have down the road will be hard to reconcile,” Hagel said in a speech last April to the National Chinese Language Conference in Washington.

Hagel has also said Japan is a crucial partner of the U.S. and that it will become more important.

But he has expressed reservations about those in Washington, led by former U.S. Deputy Secretary of State Richard Armitage, who have called for the U.S. to have the kind of relationship with Japan that it has with Britain.

“Japan represents an anchor in Asia for the U.S. But the U.S. should never put itself in a situation where we are just arbitrarily deciding ‘Well, is China more important than Japan?’ Japan’s relationship with the U.S. is special. But it shouldn’t come — nor do the Japanese want it, I believe — at the expense of developing a close relationship with China,” Hagel told the New York-based Asia Society in 2008.