The average number of Republican votes in gubernatorial and midterm Senate races in 2010 and 2014 has been about 2.8 million, according to records kept by the Texas Secretary of State. The average Democratic vote total in those races has been approximately 1.9 million. In other words, historical results suggest approximately 900,000 more Republican voters than Democratic voters in the average midterm election.
A hypothetical defection of 6 percent of Republican votes to O’Rourke subtracts about 168,000 votes from the average GOP vote total.
Even if we were to assume that all of these Republican voters fled to O’Rourke – as opposed to just staying home – that would leave Cruz ahead by approximately 564,000 votes. Could Democrats increase turnout enough to close that gap?
It would be an uphill battle, with hopes of victory resting on mobilizing groups with historically low turnout levels in midterm elections, such as young voters and Democratic-leaning Latinos. Exit polls for recent elections illustrate just how difficult this has been in recent history. Latinos, for example, made up only 17 percent of the electorate in 2014. In that year, nearly half of Latino voters backed the Republican candidate, and the Democrat lost by 20 percentage points.
But let’s imagine that O’Rourke manages to mobilize an additional 20 percent to the baseline Democratic vote – an optimistic estimate for O’Rourke. That would add another 380,000 votes to the Democrat’s total – still short of Cruz’s projected vote total by 184,000 votes.