It may be difficult to change the Legislative Council in a way that is acceptable to both Beijing and democrats, but it is not impossible. Beijing's bottom line is obvious: the 50-50 split between functional constituency members and those returned in geographical constituencies must remain, to maintain the dominance of the pro-establishment forces.
But there are still a number of alternatives that can be considered.
First, in 2016, the number of lawmakers could be increased from the current 70 to 80. The five functional seats could follow the same format as the 2012 "super seats", with candidates nominated by district councillors and then directly elected by the people. Alternatively, functional constituencies could be reformed by, for example, creating five new functional groups - for women, retired citizens, ethnic minorities, youth, and interest groups representing mainland immigrants, or voting for functional seats could be expanded to all voters working in a certain sector.
Second, the number of directly elected lawmakers could be increased from 35 to 70, thus achieving direct election of the entire council. This model would surely be rejected by Beijing, which would see it as a radical change.
Third, two chambers could - and, I believe, should - be set up: one composed entirely of elected members, either 35 or even 70; plus a new Functional Council with the same number of members, to retain the 50:50 ratio.
This model would seem to be a win-win solution; the pro-democracy camp would achieve immediate direct election of the legislature, while functional constituencies, cherished by the business sector and Beijing, would be maintained in the Functional Council.
But there are disadvantages. Changes would have to be made to Article 68 of the Basic Law, by deleting the statement that the method for forming Legco conforms to the principle of gradual and orderly change. The section covering the method of forming the legislature, and the part governing voting procedures, would also need to be modified.
Bills introduced by the government could still be passed by a simple majority, if this was the consensus among the democrats and Beijing.
To pass motions, bills or amendments to government bills introduced by individual legislators, we could consider requiring passage by the two councils, each through a simple majority vote. In this bicameral system, Legco's operation would remain the same, with a relatively powerful Functional Council acting as a check on directly elected members.
Further, if the bill was blocked by the Functional Council, a committee with an equal number of members from both councils could be set up to break the deadlock. Or there could be a yearly limit on the number of times the Functional Council could veto bills.
The first alternative is similar to the US system in which the House of Representatives and Senate set up a conference committee to hammer out solutions when required. The second option acts as a check on the veto power of the Functional Council against the lower chamber.
Finally, under a bicameral system, the Functional Council would not need super seats; rather, functional constituencies would need to be reformed, by adding new sectors. Moreover, a few of the 1,200 members of the chief executive Election Committee could perhaps be elected into the upper chamber. Under a bicameral system, the upper house could be designed to allow broad representation.
For the 2017 chief executive election, we should look to former Democratic Party chairman Martin Lee Chu-ming's model (which he subsequently withdrew), in which five candidates could be selected for the race, with a 1,200-member nomination committee based on the existing Election Committee.
Beijing would probably see this as dangerous, given that at least one pan-democrat would have a good chance of being nominated. To make it more acceptable to Beijing, we could use the 2012 election as a reference; one of three final candidates - Albert Ho Chun-yan - was a democrat. So, perhaps three, rather than five, candidates screened by the nomination committee in 2017 would be acceptable to both Beijing and most Hongkongers.
To address the concern of Qiao Xiaoyang , chairman of the Law Committee of the National People's Congress, that the chief executive must be someone who "loves the country and loves Hong Kong", all candidates competing for the three slots should swear allegiance to the People's Republic of China and the Basic Law. In this way, the political criteria of "patriotism" would be met, and Beijing would not veto any candidate to be directly elected by the people.
Clearly, designing political models that are acceptable to both Beijing and the people is vital to our stability and progress. With a chief executive election along the lines outlined here, including a declaration of allegiance from all candidates, plus a bicameral legislative system, Hong Kong can move towards universal suffrage without ceaseless internal political disputes.
Professor Sonny Lo Shiu-hing is head of the Department of Social Sciences at the Hong Kong Institute of Education