Japan must undertake a major review of the way its decades-long alliance with the United States works and adopt a more proactive approach toward its top ally after Donald Trump takes office in January, a veteran Diet member said Monday in Tokyo.

Come next year, “Japan can’t just sit back and do what it’s told to do by the United States. We must make active proposals and swiftly reform our foreign policy where necessary. Otherwise, we shouldn’t try and embark on what will become a very tough negotiation” on various issues with the U.S. under Trump, Shigeru Ishiba, a heavyweight in the ruling Liberal Democratic Party, said at the Foreign Correspondents’ Club of Japan.

Ishiba, a former defense minister and LDP secretary-general, met with Michael Flynn, a retired U.S. Army lieutenant general newly appointed as Trump’s national security adviser, a month before the historic Election Day.

“He had a very accurate understanding of how important the Japan-U.S. alliance is,” Ishiba said of Flynn.

But this is not to say, Ishiba emphasized, that the two were complacent about the Japan-U.S. relationship. In fact, Ishiba said, they had a shared understanding that it “cannot remain as it is.”

“The idea that the Japan-U.S. alliance is about America being obliged to protect Japan but Japan not being obliged to do the same, in exchange for its alternative obligation to provide bases for America, must eventually change,” Ishiba said, without elaborating.

Noting that Prime Minister Shinzo Abe expects an “extremely tough” ride in his future negotiations with Trump, Ishiba called for full-fledged preparedness — and more assertiveness — on Tokyo’s part.

“Japan must stop being a nation that changes its policy per foreign pressure, whether it’s about the economy, security or finance,” he said.

Ishiba, who narrowly lost to Abe in the 2012 LDP leadership election, has long been rumored to be next in line to lead the country. But his chances of doing so suffered a significant setback last month when the party decided to revise internal rules to allow Abe to run for a third term.

In a dig at the Abe administration, Ishiba said its rock-solid popularity is actually driven by the lack of viable opposition parties rather than genuine voter support. He also obliquely criticized Abe’s continued reluctance to tackle unpopular policies such as the consumption tax hike, calling his procrastination a sign that he may be “prioritizing self-protection.”

Ishiba didn’t clarify whether he will challenge Abe in the next leadership election. But the 59-year-old nonetheless appears to be slowly moving toward carving out a new support base among the public.

Earlier this month, he invented an array of his own cartoon “stickers” for the popular Line messaging app. The stickers depict an itty-bitty Ishiba, called “Ishiba-kun,” smiling affectionately, devouring curry rice and throwing a tantrum like a child — all featuring what some call his “kimo kawaii” (“creepy-cute”) expressions. The stickers are available for ¥120.

“I hope the stickers will help voters feel much closer to politics,” Ishiba said.