Chinese officials in Washington quietly pressured the speaker’s office to curtail visits with dissidents, according to people familiar with the situation, to avoid a repeat of her 1991 trip, when Pelosi humiliated China’s leaders by brandishing a pro-democracy banner in Tiananmen Square.

Pelosi politely rebuffed them, book-ending her weeklong tour of China by meeting human rights leaders in Shanghai and Hong Kong — while keeping some itinerary details close to the vest to avoid interference.

Yet if China’s leaders were expecting Pelosi to embark on a human rights pilgrimage to commemorate this week’s 20th anniversary of the Tiananmen crackdown, they underestimated her evolution and their own increasing leverage with top U.S. officials.

“She hasn’t changed her opinions, but she’s certainly softened her tone,” says Richard Bush III, a China scholar with the Brookings Institution who accompanied Pelosi on her Beijing trip in 1991. “She just can’t afford to be as strident.” North Korea’s nuclear test elbowed onto Pelosi’s agenda, but her mission was to discuss China’s global warming efforts ahead of December’s Copenhagen conference.

And she largely kept to that script. When The Associated Press ran a story headlined,“Pelosi Dodges Human Rights on China Visit,” the speaker declared: “Protecting the environment is a human rights issue.”

UCLA political science professor Richard Baum, who advised Hillary Clinton on China during the 2008 presidential campaign, says Pelosi needed to moderate her image in China to remain relevant. “Nancy Pelosi, God bless her, has gotten off her high horse,” he said. “It’s a question of what works. And humiliating them and making them lose face in public by shaming them doesn’t work. What does work is persistent, long-term quiet pressure.”

The contrast between Pelosi’s 2009 visit and the 1991 trip was stark. Brookings’ Bush can’t forget the impression Pelosi made on Chinese officials who grudgingly attended a state dinner in September 1991 — hours after the then-obscure San Francisco Democrat unfurled her “To Those Who Died for Democracy in China” banner in the presence of TV crews.

“The body language was just awful,” recalls Bush, then an aide for former Rep. Steve Solarz (D-N.Y.). “The Chinese officials weren’t making eye contact with her; they were staring at their plates and at each other. She couldn’t have cared less. ... I suspect they saw her as the enemy.”

On last week’s trip, Pelosi — who described China’s leadership as the “Butchers of Beijing” after the 1989 Tiananmen killings — stuck to protocol and left the banner waving to others. On May 24, the day of the speaker’s arrival, a throng of demonstrators in Beijing waved a sign reading: “Welcome Pelosi. Pay close attention to human rights. SOS.”

Pelosi, who continues to introduce pro-Tibet resolutions in the House and called for a boycott of the 2008 Beijing Olympics, pressed President Hu Jintao and other leaders on Tibet and restrictions on free speech. But for the most part, she confined her comments to what she described as “candid” closed-door meetings.

And even her low-key visits with pro-democracy activists seemed calculated to avoid embarrassing a leadership that has been historically sensitive to slights and snubs. On May 25, she sat down in Shanghai with 93-year-old Catholic Bishop Jin Luxian, a one-time dissident who was imprisoned for two decades over his calls for religious freedom.

Five days later, she visited Martin Lee — the man who gave her that banner 18 years ago — in Hong Kong, where she also met with labor activists.

Srinivasan Sitaraman, a Clark University politics professor who studies China’s human rights record, said Pelosi’s credibility on the issue has been undermined by the release of the so-called Bush administration torture memos and, to a lesser extent, by the firestorm surrounding her own 2002 briefing on enhanced interrogations. “She’s in a very delicate situation,” he said. “I don’t know how aggressive a spokesman she could afford to be.”

Pelosi, for her part, forcefully rejects such suggestions. During a press conference in Beijing after her meeting with Hu, she bristled when an NPR reporter asked: “[Are] you ... overlooking the human rights issue in favor of economic and environmental” issues? “I’m not overlooking it,” Pelosi said. “We have brought up human rights. ... Twenty years ago — I guess it’s 18 years ago — I stood in Tiananmen Square with a banner. That was my opportunity to express the concern that I, as a member of Congress, had for human rights in China and Tibet.”

Then she pivoted: “I am now speaker of the House and have the opportunity to speak directly to the president of China, to bring up the subject, on behalf of the entire Congress,” she added. “We want to increase our communication.”

Pelosi was equally diplomatic on climate change. She seemed to take it in stride when Wisconsin Rep. Jim Sensenbrenner, the sole Republican on the codel, claimed that Chinese leaders have no intention of matching the greenhouse gas limits Pelosi is pushing through the House.

“I am very discouraged at the conversation that we have had with all of our Chinese counterparts,” said Sensenbrenner, standing next to Pelosi at the Beijing press conference. “The message that I received was that China was going to do it their way, regardless of what the rest of the world negotiates in Copenhagen,” he added. Pelosi responded by describing her meetings as “hopeful” while acknowledging “the questions Mr. Sensenbrenner raises are legitimate ones.”

But if any issue underscored Pelosi’s transformation from dissenter to diplomat, it was North Korea. The speaker was the highest-ranking American official in the region when Pyongyang detonated its second nuclear test — forcing her to cajole Hu and other leaders to pressure their allies.

“That was a major subject, a topic of conversation with the Chinese leaders,” Pelosi said. “I was encouraged in that regard, that everyone knows how important it is to get the North Koreans back to the table.”

Victoria McGrane contributed to this report.