If the first part of Theory was itself entitled "theory" it was clearly because the basic building blocks of Rawls' account were provided there. In articulating the application of the two principles of justice that have been elaborated through the device of the "original position" Rawls now turns to the second stage of his main argument. This is the one in which the means of application of these principles begins to be seriously considered.
In order to begin the process of articulating the means of application of principles Rawls first lays out 3 kinds of judgment that a citizen typically has to make concerning justice. Firstly, a citizen has to come to a view about the justice of legislation and social policies. This first judgment immediately produces a problem though which is that there is recognisable conflict between different conceptions of justice. That produces the second kind of judgment required from the citizen. This concerns which kinds of constitutional arrangements are just for reconciling conflicting opinions. However, there is also a third problem that emerges assuming the first two have been settled. This concerns the point that political processes produce only imperfect procedural justice so it is necessary that the citizen determine when the judgments of the majority are worthy of being complied with. Put together these three problems the citizen has to face are "the grounds and limits of political duty and obligation".
After laying out these typical problems a citizen has to face Rawls returns to the device of the "original position" and elaborates its role in his account. Previously we were led to think that the invocation of this device would lead only to the selection of principles of justice after which the parties in the original position would return to society. Now, however, Rawls instead introduces an intermediate process between the selection of the principles in the original position and the return to society.
This intermediate process involves thus an extension of the use of the device of the "original position". After the principles of justice have been chosen the parties in this position move to form a kind of convention that is meant to describe a constitution for the society that they will move to from the "original position". Thus the parties are now moving to construct a "basic structure" after having chosen the principles of justice. The procedure by which this construction takes place is evidently regulated by reference to the principles of justice already chosen. However, one of the key problems that has to be faced now is the second difficulty of the citizen, namely, how to determine which arrangements are just for reconciling political differences.
Whilst we are still within the "original position" at this stage the "veil of ignorance" has been partially lifted given that we have principles of justice chosen. Along with these principles certain information is now released such as the natural circumstances of the society, its level of economic advance and also, apparently, its "political culture" (though it is hard to know what Rawls could mean by this).
There are two problems to deal with at this stage. Firstly, a just procedure has to be designed to arrange a just outcome. In reference to this Rawls points to the need to incorporate the liberties of equal citizenship into the constitution. Without such liberties he assumes no just procedure could be followed. However, the problem of imperfect procedural justice now arises again and requires addressing. To address it a further lifting of the "veil of ignorance" takes place which enables knowledge of the beliefs and interests men are liable to have and the political tactics they would be likely to use (which answers the earlier point about political culture but then also suggests it was otiose to mention it at the previous stage).
The two principles of justice already define an independent standard of the desired outcome. Having reached this point in the process a next stage in the development of the basic structure can take place. It involves invoking the notion of the legislature in the sense of a representative legislator who assesses the justice of laws and policies from the perspective of the independent standard.
However Rawls also accepts that the understanding of the justice of laws and policies is much more difficult with reference to the second principle of justice than with regard to the first. Violations of the first principle can be clearly seen to be unjust whereas violations of the second are harder to see. The principle of equal liberty is safeguarded by the process of the constitution which establishes a secure common status of equal citizenship. The second principle is what guides the decisions of the legislator, subject to the primary reference to the principle of equal citizenship.
Next there is required the application of rules to particular cases by judges and administrators and following of rules by citizens. When we reach this stage the "veil of ignorance" is completely lifted and we are back in society. But it is not at that stage the grounds and limits of political duty and obligation are determined as that question belongs to partial compliance theory which is formulated during the original position but after the choice of the principles of justice.
The stages of construction of a "basic structure" are thus laid out in section 31 and in section 32 Rawls turns to describing the concept of liberty that is so important in the construction of this structure. In doing so Rawls leaves aside the questions about "positive" and "negative" liberty that were so important to Isaiah Berlin to focus only on a minimal sketch of liberty referring to the parties that are free, the restrictions they are free from and what it is they are free to do. Liberty is thus understood primarily in relation to constitutional and legal restrictions so that, as Rawls puts it in the second edition, "persons are at liberty to do something when they are free from certain constraints either to do it or not to do it and when their doing it or not doing it is protected from interference by other persons".
The basic liberties are presented as a unitary whole and it is suggested that under favourable conditions it is possible to define them in such a way that the most central applications of each can be secured. Finally, it is assumed to be clear whether an institution restricts a liberty or only regulates it. Inability to take advantage of liberty is assessed by Rawls not as a constraint of liberty but as something that affects its perceived value. Inasmuch as it has value for someone liberty is the means by which they are able to attempt to attain their ends.