First, note the limited electoral impact of Hispanic voters. All other things being equal, Republicans would have to fall to 8 percent of the Hispanic vote before another state flips to the Democrats (they would lose the popular vote by almost 10 points in this scenario). For all the talk of Texas potentially voting Democrat, that doesn’t happen until Republicans drop to 5 percent of the Hispanic vote.
On the other hand, Republicans would have to win 49 percent of the Hispanic vote to win the popular vote (with other vote shares and turnout rates being equal to 2012), but they would still lose the Electoral College, 289-249. Republicans would have to improve to 63 percent of the Hispanic vote before they would win the Electoral College. This is, incidentally, similar to findings from FiveThirtyEight in 2013…
Third, we note that Republicans don’t have to put up a historically good performance among minority groups to win the election. Take the 2014 exit polls. If Republicans win demographic groups at the rates they did in that election, they would win the popular vote by around three points, and carry the Electoral College, 295-243. In this scenario, Nevada, New Mexico, and Wisconsin vote for the Democratic candidate by three points or less, while Colorado and Pennsylvania for the Republican candidate by three points or less.
Some would counter that putting up these vote shares in the midterm electorate is one thing; doing it in the presidential electorate is another. This may well be true (assuming there is no reversion to mean in turnout), but Republicans don’t have to win the election by three points (the 2014 exit polls actually underestimate Republican performance by a point, so the actual projected margin is probably four points), and don’t have to carry Colorado to win the presidency. Moreover, we account for this, at least to some degree, by controlling for race.