What key belief was held by the majority of delegates at the Constitutional Convention of 1787?

The answer is kind of complex: most of them were convinced that the Articles of Confederation needed to be amended or improved. However, after initial debates and discussion most of these delegates agreed upon the principle of a new form of government that allowed for the proper running of the country and the smooth resolution of disputes between states. James Madison's Virginia Plan was adopted as the main draft for the new Constitution and was subsequently debated, amended and ratified.