Before examining the advantages and the disadvantages of the federal state we must first define the meaning of Federalism. “In Europe, federalist is sometimes used to describe those who favour a common federal government, with distributed power at regional, national and supranational levels. Most European Federalists want this development to continue within the European Union. European federalism originated in post-war Europe; one of the more important initiatives was Winston Churchill’s speech in Zurich in 1946.”  At the same point, Federalism is a global political system in which it contain two governmental levels by virtue of the same geographical area and the same population. Those federal states governmental structure based on each of the central government and governments exist in the smaller political units called States or regions, and these small political units to give some of its political power to the central government to work for the citizens.
In the federal system, each of the central government and the state government is both drafting the laws, in the United States for example; it is imperative on the population to obey the law approved by the authority of local legislatures and the Congress. The federal system dividing the countries power and resources between the central government and state governments according to specific criteria, these criteria tend towards the central government in the country and some state governments in another country, but most federal systems provide some sort of autonomy for the states. Some other examples of federal states such as Australia, Brazil, Germany, Mexico, Nigeria and Switzerland. Most of the world states do not follow the federal system in managing their affairs, instead, they depend on the central system where all the authorities under the central government to be responsible for provincial administrations to carry on business with local survival of full legality. Thus, central authority system have greater force than the federal system.
Moving on to the advantages of the federal government, first of all we have to mention that the federal critics argued that federalism is complex, slow to change, abide an uneven evolution, leading to a disparity between regions, leading to a doubling of services and duties, a costly material, the subject of responsibilities and resources to the laws of governments is difficult and unstable.  Moreover, with regard to the criticisms, although some of them are logical and correct, they do not live up to the negatives experienced by the Central States, and is nothing compared with the positive pattern provided by the federal government, especially for multiple countries, cultures and peoples.
Another advantage is that ” Federalism offers representation to different populations. Citizens of various provinces may have different aspirations, ethnicity and follow different cultures. The central government can sometimes overlook these differences and adopt policies which cater to the majority. This is where the regional government steps in. While formulating policies, local needs, tastes and opinions are given due consideration by the state governments. Rights of the minorities are protected too.”  What is more, the second good advantage of federal government is that of it existence in a state; the central government can concentrate more on International affairs while the regional government can concentrate on organizing the local needs. Also, ” Federalism has room for innovation and experimentation. Two local governments can have two different approaches to bring reforms in any area of public domain, be it taxation or education. The comparison of the results of these policies can give a clear idea of which policy is better and thus, can be adopted in the future.” 
We can summarize the benefits of federal systems in the fact that it helps to Lead to the spread of security and internal peace, Develop common values, Encourage or lead to democratic pluralism, Protect and lead to a moderation between the differences, The losers are turning to the winners at the level of the region and finally, it get the government closer to the people.
On the other hand, the federal government comes with also some disadvantages. Federal system can lead to duplication of government and inefficient, over-lapping or contradictory policies in different parts of the country. Also, It can lead to inequality between the states and lead to damaging competition and rivalry between them. 
” Sharing of power between the centre and the states includes both advantages and disadvantages of federation. Sometimes there can be overlapping of work and subsequent confusion regarding who is responsible for what.”  At the same point, ” Federal system of government is very expensive as more people are elected to office, both at the state and the centre, than necessary. Thus, it is often said that only rich countries can afford it. Too many elected representatives with overlapping roles may also lead to corruption.”  Not to mention, the raise of the competition amongst different regions, so ; there can be a rebellion by a regional government against the national government too. Both scenarios pose a threat to the countries integrity.  Another disadvantage is that, ” Federalism promotes regional inequalities. Natural resources, industries, employment opportunities differ from region to region. Hence earnings and wealth are unevenly distributed. Rich states offer more opportunities and benefits to its citizens than poor states can. Thus, the gap between rich and poor states widens.” 
After examining both sides a main question is considered here, why not let the international and the local organizations monitor and provide the citizens with their needs? no need to pressurize the country fund and overload it with an expensive system in which it result for accomplishing stability is not guaranteed. Further, too much changes in any country government can lead to corruption and distrust from it nation and that will result the collapse of government.
To conclude from all that, It must be noted that 40% of the world’s population live in federal countries and this number is growing day by day with every transformation of new states to the federal system. Federal is a historical product, so it is the forms and variety of functioning stemming from the current situation in countries that have pursued federalism. Also, there aren’t any ready specific features of the federal system, but there are models in formation with economic and social conditions, political and cultural conditions prevailing in these countries, which means that each country keen to its own model of federalism. Federalism is not a magic recipe, where it by itself or on its own is not the solution, however, It is less worse solutions, which is the best existing alternatives, it is the second option of all for countries that suffer crises. Federalism is the only primarily form to the settlement where there is no party in a position to win the absolute.