The part of the Preamble that best addresses the issue stated is provide for the common defense.
The Founding Fathers believe that the federal government must provide for the common defense as a result of the weakness of the thirteen states under the Articles of Confederation, before the Constitution. Thus, they arrived at the conclusion that the nation needed a stronger government, including a stronger military. The Founders were careful to grant the federal government only the few, limited powers that were necessary for it to carry out its aims.