Options open to the top judges
There are a variety of ways in which the Court of Final Appeal could rule today. The options include:
Total victory for the Government
The court could reject all the arguments put forward by the abode seekers. This is what happened when the case was considered by the Court of First Instance and Court of Appeal.
It would involve the judges deciding that none of the applicants could escape the impact of the reinterpretation by the National People's Congress Standing Committee, whatever their circumstances.
All of them would then face removal.
Total victory for the abode seekers
This would occur if the court accepted the abode seekers' arguments on the Basic Law requirement that interpretations by the Standing Committee do not affect judgments that have been delivered previously.
It would mean that Chinese citizens born before the reinterpretation on June 26, 1999, would be able to benefit from the landmark court rulings of January 1999. They would be eligible for right of abode if they had a parent who became a Hong Kong permanent resident before the reinterpretation.
Lawyers for the abode seekers estimate this would affect about 130,000 people.
A more limited victory for the abode seekers
The court could limit the effect of the above approach by ruling that only those who asserted their rights before the reinterpretation qualify.
The court would then probably have to decide what amounted to an assertion of rights, such as making a claim for the right of abode.
This would significantly reduce the number of people who have the right, but it would still involve thousands.
A ruling based on the expectations of abode seekers
Another basis upon which the court could rule in favour of the abode seekers is to find that they had a legally binding expectation that their rights would be determined in the January 1999 court judgments, rather than the reinterpretation.
The numbers concerned are difficult to quantify. It may depend on the Government looking at each individual claim to see which applicants had such an expectation.
A ruling on the Government's 'concession'
The abode seekers challenge the limited way in which a 'concession' given by the Chief Executive, allowing certain applicants who would otherwise have been affected by the reinterpretation to have the right of abode, has been interpreted and applied by the Director of Immigration.
If the court ruled in favour of the abode seekers on this ground, it would be expected to establish different conditions to those applied by the director. For example, it may say that those who applied for legal aid in order to pursue their abode claim fall within the concession.
The numbers concerned would be relatively small and would depend on the conditions imposed by the court.
A ruling in favour of those who arrived before the handover
This would affect several hundred applicants who arrived in Hong Kong before the handover and stayed on after July 1, 1997.
The abode seekers argue the reinterpretation cannot apply to them because it concerns the Basic Law, which was not in force when they came to Hong Kong.
An abode seekers' victory, but with a catch
With the exception of those who came to Hong Kong before the handover, abode seekers who are successful may be told by the court that they must still return to the mainland in order to make their applications for right of abode.