How many seats would go to country X, Y, Z?

The precise allocation of seats will have to be determined by international negotiations. It is therefore speculative to say how many seats would go to a particular country. It has to be noted that the seats would not be controlled by governments but by individual independent delegates. Here and here you can find two publications that look into possible models.

To what extent would populous countries like India and China be able to dominate an assembly through their share of seats?

If seats in a Parliamentary Assembly were allocated directly proportional to population size, then approximately 20 percent would be held by delegates of Chinese citizens and 17 percent by those representing citizens of India. The 128 states with the lowest population size would be represented by around 8 percent of the delegates. A directly proportional allocation would thus marginalize an overwhelming majority of countries and for this reason is not considered a valid democratic option at this time. Instead we recommend a graduated allocation of seats according to the principle of degressive proportionality, in which smaller states have slightly higher representation proportional to their population. In proposed models of this nature, Chinese delegates would have a share of seats between 3 and 10 percent and Indian members between 2.8 and 9 percent. Finally, it needs to be noted that delegates would cast their vote individually and not en bloc.

How would the seats in the proposed Parliamentary Assembly be allocated?

The precise allocation of seats in a Parliamentary Assembly will have to be determined by international negotiations. Unlike the composition of the UN General Assembly, a key feature of a Parliamentary Assembly should be that the number of delegates to be elected from the member states is graduated, with population size being an important criterion. However, to achieve a balance between the principles of democratic representation ("one person, one vote") on the one hand and the equality of states on the other ("one state, one vote"), the principle of degressive proportionality could be applied, as in the U.S. Congress and in the European Parliament. This means that the citizens of small countries would be relatively better represented per capita than those from large countries. Here and here you can find two publications that look into possible models.

How many delegates would a Parliamentary Assembly at the UN comprise?

The size of a Parliamentary Assembly should constitute an optimal balance between representativeness and efficiency. The smaller an assembly would be, the more efficient it could work but the less representative and democratic it would also be. The upper limit for efficient work that at the same time would ensure optimal representativeness lies approximately between 700 and 900 members. This is the size that most of the models take as a basis for the distribution of seats. For comparison, the European Parliament is a 736-member body and the Indian national parliament includes 802 members.

How would it be possible to strengthen the independence of delegates from their governments?

While delegates from autocratic regimes may, to a degree, act according to the instructions of their governments, the use of secret ballots, seating arrangements by political groups, and other procedural constraints would minimize non-democratic governments’ influence on the independence of delegates. The Statutes of a Parliamentary Assembly, for instance, could prohibit governments tracking the voting behavior of individual delegates or unilaterally recalling delegates during their term of office.

If universal membership is envisioned, what influence would non-democratic states have?

According to the 2016 Freedom House analysis on democracy, 125 of 195 countries in the world are “electoral democracies.” According to various models for the allocation of seats, a majority of the assembly’s delegates would come from democratic states. The democratic character of an assembly could be ensured.

How can citizens of states without democratic elections be represented?

In countries without adequately free and fair elections democratic representation of the citizens in a Parliamentary Assembly will be very difficult. Nonetheless, such countries should be allowed to be represented as long as the delegates at least are chosen from within the constitutional national parliament, inclusive of opposition factions. An appointment through the government would have to be impermissible, and rules allowing an assembly to judge the independence of its own members should be considered.

How are the delegates elected?

A Parliamentary Assembly’s member states initially should be able to decide whether to have their delegates chosen by direct elections or indirectly from within their national parliament. In the latter case, the selection of delegates should reflect the existing political spectrum as closely as possible. In addition, delegates of regional parliaments and parliamentary assemblies could complement national delegates. Some have suggested the possibility of including cities and local authorities as well. Eventually, all delegates should be directly elected by the world's citizens.

From which countries could delegates to a Parliamentary Assembly be sent?

A Parliamentary Assembly at the United Nations would be open to all member states of the UN.