So one of the dictums of American history I’ve always been taught is that it took the unifying effect of the civil war for Americans to see their country as one nation rather than an alliance of states. I was always taught the examples that Americans from this period referred to it as “these United States” rather than “the United States” or that if asked an American living in the post revolutionary era would consider themselves as principally a” Pennsylvanian, Virginian, South Carolinian or New Yorker etc” rather than an “American”.

This is really a misunderstood element of American history, and one that has been debated at length by historians. A unified American identity existed long before the Civil War, but what is true is that the states would fall back on a "state's rights" argument from time to time when federal policy disagreed with the sentiment in their region, and this could be much more extremist in the antebellum era than it later became. But it has never gone away: famously, federal troops were sent into Arkansas and Alabama in the 50s and 60s when they refused to comply with federal law to desegregate. More recently, there have been efforts to defy federal law on gay marriage, and lawsuits over Obamacare, and lawsuits over sanctuary cities and ICE's authority and governors withdrawing National Guard troops from their borders.

The truth of the matter is, citizens of the United States have long considered themselves both a citizen of the entire country and the citizen of a state. There's no shortage of Texans today calling themselves "Texans" or New Yorkers "New Yorkers" or even Iowans calling themselves "Iowans". But they also consider themselves Americans. This was the same in the antebellum period, and while Americans' "state identity" may have taken prominence during certain political flash-points at that time, it wasn't a continuous view throughout the period, and on the whole, it wasn't an entirely different relationship than it is today. It was just more contentious whenever there was contention.

Going back further into American history, there are several events that historians have argued helped shape a unified national identity:

Jill Lepore argues in her book The Name of War: King Philip's War and the Origins of American Identity that the formation of a unified American identity began as early as the 1675-76 war in the title. This would have been British-American, certainly, but still a unified cross-colonial identity. She backs this up with similar arguments made in earlier works such as Out of the Wilderness: The Emergence of an American Identity in Colonial New England by John Canup, Colonial Identity in the Atlantic World, 1500-1800 ed. by Nicholas Canny and Anthony Pagden, and Imperatives, Behaviors, and Indentities: Essays in Early American Cultural History by Jack P. Greene.

In fact, the first indication of something approaching a unified British-American identity comes from Nathaniel Ward's The Simple Cobbler of Agawam written in Massachusetts and published in 1647:

"Weepe not for him that is dead, neither bemoan him; but weep for him that is gone away and shall returne no more to see his Native Country. Divers[e] make it an Article of our American Creed, which a celebrate Divine of England hath observed upon Heb. 11. 9. That no man ought to forsake his owne countrey, but upon extraordinary cause, and when that cause ceaseth, he is bound in conscience to returne if he can: We are looking to him who hath our hopes and seasons in his onely wise hand."

So, even before 1700, there were indications that English speakers in America had begun to see themselves as a unified people. They were still English people (and, later, British people), and they were contrasting themselves with the Native American nations whom they lived near to, but they were still coming to see themselves not as Virginians and New Englanders and Marylanders and Carolinians. They were instead seeing themselves as Americans, with a unified American-English or American-British identity.

This culminated in a unified American identity during the American Revolution. There is no shortage of surviving literature that indicates that the colonies had started to see themselves as one people, but a good starting place would be the writings of Noah Webster, who wrote the first American dictionary. In one essay, he writes:

"As an independent nation, our honor requires us to have a system of our own, in language as in government...[T]he taste of her writers is already corrupted, and her language on the decline...Several circumstances render a future separation of the American tongue from the English necessary and unavoidable..."

A unified Patriotism swept over the colonies, which ushered in a Constitution that applied to all the states, unified under one government as the United States. These national sentiments came to the fore most prominently on the Fourth of July celebrations every year, which were celebrated across the North and South alike, and in every state that joined the Union. An illustration of the 1796 celebration in Charleston, South Carolina, survives, and, as described in Celebrating the Fourth: Independence Day and the Rites of Nationalism in the Early Republic by Len Travers, the illustration depicts guns of the fort firing a salute, while bathers take a swim at the beach as they watch the spectacle.

Travers' book is a study of antebellum celebrations of Independence Day in Boston, Philadelphia, and Charleston, South Carolina, and Charleston was little different from its northern neighbors in regards to the celebrations. The state celebration of Palmetto Day lost its importance in the 1780s in favor of the new national holiday, and while the celebrations could sometimes be muted in comparison to Philadelphia or Boston, that was due to the severe heat in pre-air conditioning days, as Travers argues. Nonetheless, beginning in the 1790s, the banks and most businesses closed for the day, and the people of South Carolina celebrated the ways they liked best, with fireworks and alcohol:

Charlestonians also had a reputation for being a hard-drinking lot...[They] did not let their famous reputation suffer on the Fourth of July, and indeed many started early. "We began the celebration of Independence Day," reported Edward Hooker, "in the Carolina way, this morning, by participating in a flowing bowl of Egg-Knogg."

The day would also be celebrated with Patriotic, nationalistic speeches, and often, a reading of the Declaration of Independence. Travers goes on to write that these celebrations only increased over the years, with the Independence Day celebrations being used to drum up support for the War of 1812 in Charleston, where initial support was not all that enthusiastic. After the 1815 celebration, Travers reports on the Southern Patriot newspaper's description of the event:

"What a day!" exclaimed the editor of Charleston's Southern Patriot in an 1815 article entitled "The Fourth of July." "What happiness, what emotion, what virtuous triumph must fill the bosoms of Americans!" Despite America's lack of preparedness in the late war, despite the superior war machine of the British enemy, despite a war fought on several fronts, and the burning of the national capital, he maintained, "The foe is discomfitted and fled. We have triumphed." In the past, the writer continued, Independence Day orators had invoked the patriotic sentiments attached to events of the Revolution, forty years before. ''To what feelings will the orator now appeal?" he asked, and, answering his own question, "To those of manly pride, and pious gratitude to Heaven, and confidence in ourselves and our resources." Most of all, he declared, Americans could feel proud and rejoice on this day, "because you have established a NATIONAL CHARACTER."

These celebrations continued enthusiastically throughout the 1820s. It was only with the Nullification Crisis of 1832-33, and the lead-up to it, that South Carolina's view of a united "national character" began to be challenged.

It is true that there could be quite fierce arguments from time to time about the role of federalism in relation to the states in the antebellum period, and the Nullification Crisis proved to be the most significant such event. But rather than pushing the country apart, outside of South Carolina, it actually pulled the country together with a unified identity, at least for a short while. An important event that happened during the lead-up to the Crisis was the Webster-Hayne Debate, in which Senator Daniel Webster (no relationship to Noah) from Massachusetts and Senator Robert Hayne from South Carolina had a heated, and lengthy, debate on the Senate floor about the role of the Constitution and the federal government. Their speeches were widely published in newspapers and pamphlets throughout the United States, and Webster's argument was, at that time, largely seen as having come out on top. His speech ends with:

"Let us cultivate a true spirit of union and harmony. In pursuing the great objects which our condition points out to us, let us act under a settled conviction, and an habitual feeling, that these twenty-four States are one country. Let our conceptions be enlarged to the circle of our duties. Let us extend our ideas over the whole of the vast field in which we are called to act. Let our object be, OUR COUNTRY, OUR WHOLE COUNTRY, AND NOTHING BUT OUR COUNTRY. And, by the blessing of God, may that country itself become a vast and splendid monument, not of oppression and terror, but of Wisdom, of Peace, and of Liberty, upon which the world may gaze with admiration for ever!"

(...cont'd...)

The territories that became states were often settled by frontier types (Daniel Boone / Tennessee for example) and that is usually part of the foundation myth. People didn't need college football to decide to cheer for their state and just because there wasn't a state doesn't mean there wasn't a local culture there. As an example see Louisiana, the borders of the French territory weren't the same as the eventual US state, but the New Orleans / Cajun culture existed before the state and became part of the state's heritage as soon as the state was formed.

I don't know how Wisconsinites specifically felt about their state's culture and heritage, but they tended to be descended from Northern European Protestants who believed slavery was wrong and were loyal to the union, so I'm sure it didn't take a lot for them to look down on the traitors who were fighting to keep men in bondage. Support for a cause can be fomented by riling people up in opposition to some other cause.