The happy Union of these States is a wonder their Constitution a miracle their example the hope of Liberty throughout the world.

In this sentence Madison celebrates the American federal experiment as something historically unprecedented: independent states choosing to bind themselves into a durable union under a written constitution. Calling the Union a “wonder” and the Constitution a “miracle” underscores how improbable such a voluntary, large-scale republic seemed in an age when many believed free governments could not survive over extensive territory. The final clause—America’s “example” as “the hope of Liberty throughout the world”—frames the United States not merely as a national project but as a model with international stakes: if the Union and Constitution succeed, they strengthen the cause of constitutional self-government elsewhere; if they fail, they may discredit it.