The first argument put forward for a federalist legal order is that a central government is too cumbersome when it comes to legislating over region specific matters. Take the United Kingdom, for an example. The UK government in London was often required to legislate on agricultural and fisheries matters that related to issues over 1,000 miles away in the North of Scotland. In this scenario, it would be unrealistic to expect the central government to have the requisite local knowledge and understanding required to make an effective decision for the prosperity of the region. In this sense, it is argued that a federalist legal order is more desirable, on the basis of making 'small time' decisions that affect specific localities with which it is acquainted. This has proven to be one of the strongest features of the federalist system, which largely relates to local people and their specific needs, and engages in political and legal decision making 'closer to home'.
Another very strong argument in favour of federalism is the fairer representation afforded by local and regional government. Again, the UK provides a fine example of how this would work in practice. Broadly speaking, the UK is divided into a left wing political party (Labour) and a right wing political party (Conservative). The Conservative party have a strong hold over the South East of England, which makes up a sizeable proportion of the population although covers limited geography. Labour have a traditional stronghold in Scotland which accounts for one third of the land mass but only one tenth of the population. In this sense, federalism would provide a fairer system of representation by allowing regional governance that could account more easily for local tastes and opinions and provide an altogether more representative picture of the nations political favour.
On top of these reasons, federalism lightens the load as respects central parliamentary time, freeing up national level politicians to consider more strategic rather than operational matters. This frees up resources and streamlines the process overall, although it does bring with it the complexities of an additional layer of authority. However, provided the legal system is well structured and defined in a codified form, federalism can make for more efficient governance and an overall fairer political and legal system, as well as bringing a host of other governmental and internal benefits to the table.
Federalism has grown in popularity over the last century or so, and this is largely down to its particular successes throughout the world. Much the creation of academic thinking and commentary, federalism brings about a system of governance that keeps the people happy, promotes local affairs, and leads to significantly more favourable governance nationwide. For these reasons, it is quickly becoming the favoured method of government worldwide, and has been adopted in centralist countries and larger regions alike to promote and maintain the diversity necessary for effective regulation at a national level.