Donald Trump is holding a rally on Saturday in Phoenix, Arizona where he expects 9,000 people to show up. He's focusing on immigration and crime — which has gone from an offhand comment during his presidential campaign launch last month to the central theme of his run.
Accordingly, Trump's going to be introduced by Jamiel Shaw Sr., whose son was killed by an unauthorized immigrant in 2008. Shaw's become a visible figure among conservative opponents of unauthorized immigration (he's testified before Congress multiple times about the death of his son).
Arizona isn't an early primary state. But it's been the epicenter of populist, anti-immigration sentiment for Republicans for several years now. Trump's going to appear with Maricopa County Sheriff Joe Arpaio — who's become nationally famous for his emphasis on rounding up unauthorized immigrants (as well as the conditions of the "tent cities" he's put them in). And the rally is sponsored by the Maricopa County Republican Party.
But Arizona's GOP is also a microcosm for the deeper split in the Republican Party. Both the state's senators, John McCain and Jeff Flake, were original cosponsors of the comprehensive immigration reform bill the Senate passed in 2013 — and both have criticized Trump for the inflammatory comments about immigrants that have become a hallmark of his presidential campaign (repeatedly calling them rapists and murderers, and saying that Mexico and other countries aren't "sending their best people").
But the criticism from McCain and Flake is exactly what Trump says distinguishes him from the rest of the Republican Party. His speech Saturday, according to press reports, will criticize other Republican candidates for president for not taking the immigrant threat seriously — because they're beholden to business interests that want to encourage immigration.
In other words, Trump is claiming that because he's rich enough to finance his own campaign, he's able to speak the truth about immigration in a way other candidates can't.
The speech was originally scheduled to take place at a smaller venue, but got moved to the convention center this week due to a surge in demand, according to Trump's campaign.