In a recent blog post, Jacqueline Gehring argued that all the hand waving about "Brexit," the UK's decision whether to leave the European Union, and an imminent Trump victory were, at best, overblown. She claims that Great Britain has always been wary of its relationship to Europe and the EU, and public support for a Brexit has always been strong.

Recent concerns about terrorism and immigration had little to do with rising xenophobia or populism, she continues, which means the event ultimately speaks not at all to the current American political scene and the possibility of a Trump presidency.

I respectfully disagree with my right honorable colleague. Britain's "Leave" vote may have been the result of long-simmering Euroskepticism, but without the rise of the UK Independence Party (UKIP) and its anti-immigration rhetoric, I’m doubtful Leave would have won. In fact, the successful rise of UKIP in the 2015 general election and its ability to jettison the United Kingdom from the EU speaks directly to why Democrats ought to seriously worry about their electoral prospects in the fall.

Let me be clear: I am a student of Congress and American politics. I have a keen interest in British politics, and I teach a study abroad course on it, but I would not call myself an expert. Still, I am familiar with the work of Matthew Goodwin, who has co-authored two books on right-wing politics in the UK (Revolt on the Right and UKIP) — focusing primarily on the rise of UKIP, which is led by Nigel Farage. I recommend both wholeheartedly.

Goodwin and his co-authors make three key claims in both books. First, UKIP supporters are all Euroskeptics, but not all Euroskeptics are UKIP supporters. In fact, Goodwin et al. write, UKIP’s growth has been fueled by combining Euroskepticism with "potent appeals on domestic issues."

They continue:

The "left behind" voters flocking to UKIP are angry about immigration and the failure of the mainstream parties to manage it, and alienated by a political class which they feel does not listen to them, and has done nothing to make their lives better.

Conservative opponents of the EU have always stressed that their quarrel with the EU stemmed from sovereignty rapidly slipping away from Westminster, as well as the overly burdensome regulations imposed by unelected Brussels bureaucrats. UKIP’s arguments against the EU encompassed that and more. The party's criticisms have been far more visceral and emotional: that the EU represented an attack on the Englishness itself.

A second claim made by Goodwin and his co-authors is that UKIP increasingly saw its growth potential not among disaffected Tories but among disaffected Labour voters. Goodwin and Caitlin Milazzo write in UKIP that "Labour voters had actually been moving away from the party since the 1990s, ever since it had joined the so-called liberal consensus on Europe and immigration."

They continue, "This loss of faith and the erosion of the left’s traditional base would soon provide an opening for Farage, leaving a reservoir of disgruntled people who had once voted for Labour." To grab Labour voters required an appeal beyond Euroskepticism.

Finally, Goodwin documents in public opinion polls both the rise of immigration as the most important issue facing Britain and the perceived inability of the Conservatives or Labour to do anything about it. As Gehring argues, support for Brexit does not seem to ebb and flow with opinions on terrorism or immigration in public opinion polls. More important is the critical mass of voters who feel powerless, looking for a mechanism to voice their displeasure to both the major parties. That vehicle was the referendum on EU membership — a vehicle provided by Prime Minister David Cameron and happily exploited by UKIP.

UKIP has long been castigated for its questionable electioneering tactics, particularly when it came to its billboards and posters. Here is a UKIP poster from the 2014 European Parliament elections:

Here is another, employed by the Leave campaign in the lead-up to the Brexit vote:

Both make emotional and visceral arguments about immigration — quite different from the traditional conservative arguments focused on the growth of a European superstate or the EU’s democratic deficit. Put simply, the arguments made against Europe by UKIP and the Tories were different — and I claim that UKIP’s emotionally charged argument was essential to Leave winning the campaign.

And, importantly, UKIP has been making exactly these arguments against the EU for some time — not just during the referendum campaign.

David C. Parker is an associate professor of political science at Montana State University. He is the author of Battle for the Big Sky: Representation and the Politics of Place in the Race for the U.S. Senate and The Power of Money in Congressional Campaigns, 1880-2006.

This post is part of Mischiefs of Faction, an independent political science blog featuring reflections on the party system. See more Mischiefs of Faction posts here.