The current threshold to win any vote in Texas is a simple majority of those who vote. While there are examples of greater thresholds around the world related to political separation, such as the imposition by the Canadian Supreme Court of an arbitrary 55 percent threshold for Quebec to exit, there is no similar precedent in Texas for popular votes. There is no question or debate about that aspect of the referendum. Rather, what’s more interesting is predicting the number of votes that will be required to win.

Since the threshold to win a Texit vote is a simple majority, it will take 50 percent plus 1 of those who cast a vote in the referendum. In the modern-day independence referenda, voter turnout is exceptional. In some instances, over 90 percent of those who are eligible to vote do so. The Scottish referendum turnout of 84.6 percent was the highest recorded for an election or referendum in the United Kingdom since the introduction of universal suffrage. The voter turnout for the Brexit referendum was 72.2 percent. The message is clear: when people finally get a real choice on the ballot, they show up.

By estimating a high-average 85 percent or higher voter turnout, we can calculate the number of votes it will take for Texit to carry the day. With 15,101,087 currently registered voters in Texas, the number of votes required to win is likely to be between 6,417,963 and 7,550,544. To put that figure in perspective, that is slightly less than all votes cast for all presidential candidates in the 2016 general election.

Like all elections, it will all come down to retail politics, excelling in the fundamentals of getting the message out and getting voters to the polls. Whichever side does it most effectively will win the day. Nigel Farage, former leader of the U.K. Independence Party, on the eve of the Brexit referendum, summarized what it would take to win.

“The Leave side can only win if we have an effective ground campaign comprising of activists from across the political spectrum working together.”