Donald Trump’s Arizona victory on Tuesday solidified his position as the only candidate with a realistic path to winning a majority of delegates going into the Republican National Convention — but there are a number of factors still working against him.

Before getting to those factors, it’s worth noting where the race stands at the current moment. Following Tuesday’s contests in Arizona and Utah, Trump has 754 delegates, Sen. Ted Cruz has 465 and Gov. John Kasich has 143. (Note: This is a slightly higher number for Trump than the Associated Press estimate, but is based on the fairly safe assumption that Trump will take the remaining delegates in Illinois and Missouri once all of the results become official.)

To get to a 1,237 delegate majority, Trump needs to win roughly 54 percent of all delegates outstanding, an improvement over the 47 percent he’s won so far. At this point, it is mathematically impossible for Kasich to win outright and for Cruz, it’s mathematically improbable, as he’d have to win about 86 percent of remaining delegates.