As Chinese President Xi Jinping considers how to respond to Hong Kong's unprecedented pro-democracy civil disobedience movement, he faces a series of risky choices.
Some analysts say those options range from getting tough with the tens of thousands of Hong Kong activists who have been occupying city streets since Sunday to taking a conciliatory approach toward the protesters.
So far, Xi's government has refused to back down on its August 31 ruling that Hong Kong can hold its first direct election for its leader only if all candidates are strictly vetted by a largely pro-Beijing nominating committee.
Hong Kong pro-democracy groups have condemned that ruling, saying it would prevent Beijing's critics from becoming candidates for chief executive in 2017, the earliest date on which Hong Kong can stage an election for the post under a system of universal suffrage.
Maintaining no compromise approach
New York University School of Law professor Jerome Cohen said Xi may decide simply to stick to his current policy, rejecting any concessions on the rules for how chief executive candidates can be nominated.
"On the one hand, that could discourage people in mainland China from getting any ideas from Hong Kong that rioting can win them freedom," said Cohen, who specializes in Chinese law. "On the other hand, if Xi maintains a rigid posture, things are likely to get worse in Hong Kong."
Cohen said the situation in mainland China could deteriorate as well if the Hong Kong protests drag on.
"Information about Hong Kong will seep into mainland China because of leakages in its great firewall [of Internet censorship]," Cohen said. "Mainlanders who come to Hong Kong have various means of communication that are not immediately subject to censorship. So this communication could be a kind of candle that lights a much hotter flame of consciousness that would threaten China's Communist regime, which already is under great strain."
To avoid that scenario, Beijing could deploy People's Liberation Army troops in the autonomous Chinese territory to help Hong Kong police to clear the streets of demonstrators, many of them students. China drew Western condemnation for using the PLA to stage a deadly crackdown on student-led pro-democracy protests in Beijing's Tiananmen Square in 1989.
Hong Kong's Beijing-backed chief executive, Leung Chun-ying, has tried to reassure residents that a similar PLA operation will not happen in the international financial center. But he has also called for the civil disobedience campaign to end immediately, saying it will not succeed in pressuring Beijing to change its policy.
The protesters see Leung as an obstacle to democratic reform and want him to resign. Many were outraged when his police force fired tear gas and pepper spray at pro-democracy activists who began blocking the streets September 28.
"If Leung is fired, his assurance [about the PLA] goes with him, perhaps, and several thousand soldiers could leave their Hong Kong barracks [to act against the protesters]," Cohen said.
But any Tiananmen-style repression in Hong Kong could create additional problems for President Xi.
Consequences of a crackdown
Jim Reardon-Anderson, a professor of Chinese studies at Georgetown University, said Chinese troops would face unique challenges in dispersing Hong Kong's demonstrators.
"The physical conditions are different in Hong Kong," Reardon-Anderson said. "We have a much larger gathering of people than in Tiananmen Square, and they are concentrated in a much tighter area [on the streets]. It's not obvious how a PLA force would remove crowds of that size and density from that type of location."
Princeton University international affairs professor Martin Flaherty said images of any PLA action against protesters also would be transmitted around the world by Hong Kong's local and international journalists, who operate under press freedom laws that do not exist in mainland China.
"Because of the media, that would be a complete disaster for China," Flaherty said.
Reardon-Anderson thinks the economic costs of such a disaster would be significant.
"Any crackdown in Hong Kong would send a message throughout the region that would be extremely harmful to the Chinese economy in a way that Tiananmen was not, despite the [Western] sanctions [that Beijing faced after 1989]."
A crackdown could also increase Taiwan's opposition to China's position that the island should re-unify with Beijing under the same "one country, two systems" formula that grants autonomy to Hong Kong but leaves foreign policy and defense matters under Chinese Communist Party control.
Flaherty said the Chinese government appears to be making the calculation that it is worth alienating Taiwan in order to get whom it wants as Hong Kong chief executive. He said that would represent "quite a sacrifice" for Beijing.
Path of conciliation
Xi could take several steps to address the Hong Kong protesters' demands.
One conciliatory move, said Flaherty, would be to remove Leung as Hong Kong's leader.
"There is a precedent for that - one of the largest protests in Hong Kong was in reaction to Article 23 [an unpopular government-backed national security bill]. The chief executive responsible for it, Tung Chee-hwa, was removed," he said, referencing a July 2003 demonstration that drew half a million people.
Tung resigned in March 2005, citing health problems. He had faced strong local criticism for his handling of Article 23 and other issues, leading many residents to suspect that Beijing pressured him into quitting.
Tung enjoyed a public approval rating of just 47.9 percent when he stepped down, according to a Hong Kong University tracking poll. The same poll puts Leung's latest approval rating at only 42.6 percent in September.
But Flaherty said Leung's departure likely would not be sufficient to resolve Hong Kong's political crisis, as the protesters have other demands specifically related to electoral reforms.
New York University's Cohen said Beijing would have to find a way for a Hong Kong pro-democracy leader to be nominated as one of up to three candidates whom it says could run for chief executive in 2017.
He said that would be a particularly risky move for the Chinese government. "If there are three candidates - two favorable toward Beijing and one a democrat - the two Beijing loyalists could split the pro-Beijing vote," Cohen said.
Princeton's Flaherty said compromising over the nomination process may be Chinese President Xi's "least bad option."
"It would allow Hong Kong to continue its role as a financial gateway to rest of China, serving as a model for those who want more incremental change in the country," he said.
Jim Stevenson and Sarah Williams contributed to this report.