Original sentence: Despite this, the loose coallition was able to defeat the greatest military power of its day.However, some in Congress were unsatisfied with this, and considered the central government too weak.However, the civil war shattered this equilibrium, with the federal government waging war against break-away states.It has been argued that this test of the system was due to its being tied in its own contradictions of "self-determination" regarding the issue of slavery, and that the Civil War strengthened the nation's unity.The  Articles of Confederation deliberately created a weak federal government, dedicated to the independence of the states, without even the power to raise troops in wartime.Therefore, the "Founding Fathers" of the (federal) United States devised a system which prevented the national government being ineffectual without undue interference in the affairs of the states.They thought that it might not be able to respond efficiently to serious crises in future
Edited sentence: Despite this challenge, it may be argued that the Civil War strengthened the nation's unity.It has been argued that this test of the system was due to its being tied in its own contradictions of "self-determination" regarding the issue of slavery.Through experience with too weak a system (see Articles of Confederation) which could not respond adequately or efficiently to serious crises and with innovation (and, it is argued, borrowing), the "Founding Fathers" of the United States devised a system which managed to maintain a fairly steady equilibrium (though with great give-and-take) between states and nation except through the period of the Civil War where this equilibrium was greatly tested