On today's Planet Bob, merger is seemingly more common among established alliances, instead of just recently established micros. The reason for this is simple entropy, despite the fact that I believe CN to have a decent amount of life left in it, the older alliances become, the more likely it is for them to go into decline, a state which often leads to merger. It takes a lot more effort to keep an alliance going for five years than it does for one year, so it is significantly less likely for an alliance to last for five than for one. Sometimes this decline leads to disbandment and migration (often referred to as annexation, a term I believe to be inaccurate as it implies that the disbanding alliance is not making the decision), in which an alliance decides to disband and to encourage its members to move to another specified alliance, often one with which the now disbanded alliance shared a close bond (one example being when TFD disbanded and most of its former members moved over to NATO).
The other option is merger. In a merger, two or more alliances cease to be and come together to form one big, new alliance. The main problem with mergers is that they often don't last as the cultures of the merged alliances often clash and don't work together as hoped. This leads to the splintering of the newly formed alliance. However, what if there was a way to get the best of both worlds: give the cultures of the alliances their own space so they may continue on, but also create a central authority to share the resources of each alliance to the benefit of all parties. This would especially be helpful in cases where three or more alliances want to come together as more alliances means more cultures to potentially clash.
Enter the concept of federation. In a federation, the previously independent, now constituent alliances maintain a level of sovereignty, but they also establish a central government to manage the entire federation, which can also have the power to constrain or limit the authority of the constituent alliances in some or all spheres by imposing federal policies, laws, and decisions. The only current example that even approximates a federation is the bloc Die Linke, comprised of the alliances LSF, UCR, and SWF. However, Die Linke is much more like a confederation than a federation. While the terms of its establishing treaty prohibit secession like a federation, unlike a federation its member alliances are still treated as fully sovereign entities. There is a central committee that must approve of bloc-wide treaties and of new new members of the bloc, but there is nothing to prevent an alliance from holding or signing treaties individually, so they can still carry on their own foreign affairs if they wish to. All the members of the bloc are also completely in control of their own internal affairs, and despite the fact that all members are members of all the member alliances, through the dual membership clause, members cannot vote on internal matters (anything that does not affect the bloc as a whole, presumably) outside of their own alliance, and nor can the central authority impose any sort of internal policies on the member alliances that would in any way supersede their own, individual internal policies and affairs.
This makes Die Linke a loose association rather than a strong association. If three or more alliances were to come together, instead of merging or forming a Die Linke-esque loose association, they could form a federation. In a federation of alliances, the constituent alliances would retain some sense of sovereignty, but there would be a central authority which would exercise full sovereignty on behalf of the federation. To illustrate how such a federation might work, here is a hypothetical example of one:
Three alliances A, B, and C come together to form a federation. This federation is called the ABC Federation (because names don't have to be creative in hypothetical examples). Each alliance keeps its own government and its distinct character, including its forums and in-game AA. In the ABC Federation, a member of alliance A is simultaneously a member of the ABC Federation
Alliance A. However, only ABC Federation elected officials can see the forums of more than just their home alliance (A, B, or C) and the ABC Federation central forums. Everyone else can
see the forums of their home alliance and the ABC Federation central forums.
The ABC Federation has a central government comprised, in part, of a Legislative Council, whose nine members are elected every three months from the constituent alliances of the Federation (three from each); these elections take place on the constituent alliance's own forums. This Council has the power to make Federation-wide law which is binding on all the constituent alliances, their members, and the Federation as a whole; all legislation passed by the Council must be signed by the Federation's President to become effective, which gives the President the option to veto legislation (a veto may be overturned by a unanimous vote of the Legislative Council).
The Federation's central government also contains the President of the Federation, who is directly elected by all members of the Federation on the Federation's central forums once every three months (offset so the Presidential elections do not coincide with the Legislative Council elections). Any Federation member may stand for election to the Presidency. The President then nominates a number of Federation members to serve in his/her Cabinet, which includes a Secretary of Foreign Affairs, a Secretary of Defense, a Secretary of Commerce (in charge of economic and fiscal matters), a Secretary of Internal Affairs (in charge of immigration, education, and general membership concerns), and a Secretary of Justice (in charge of internal security and serves as chief prosecutor). All nominations must be confirmed by the Legislative Council. The President also nominates three Federation members to serve on the Judicial Committee of the Legislative Council, an autonomous committee of the Council. This committee serves as the court of final appeals for all the constituent alliances' judicial/court processes. Though the President may veto legislation passed by the Legislative Council, even if the President signs a piece of legislation, the Secretary of Justice may submit laws to the Judicial Committee, after which the Committee may invalidate the law as being unconstitutional, per the Federation's Charter. The Secretary of Justice may do the same for laws or policies passed by the governments of the Federation's constituent alliances, and a designated (by the constituent alliance in question) official or body of each constituent alliance may sue for the invalidation of any Federation law, policy, or executive action by the Judicial Committee. The Judicial Committee has the additional power to resolve disputes between constituent alliances.
Given that members of each constituent alliance are dually members of the entire Federation, the Federation will establish a uniform policy for transferring membership among the constituent alliances which is much less involved than becoming a member from outside the Federation. This means that members can easily move between the constituent alliances, and the policy for such moving is set by the Federation, but that those outside the Federation can only join the Federation by becoming a member of one of the constituent alliances and that each constituent alliance sets the policy by which this can happen. This is an example of the federal character of this Federation, in which sovereignty and governing power is shared by the Federation and its constituent alliances.
Obviously, there would be many more details that would need to be worked out, but this provides a basic framework under which such a federation could be formed. I apologize for the longer nature of this entry, but federation is a somewhat complicated idea and I wanted to do it justice.