Today's foreign policy and immigration speech by Donald Trump explains, in a nutshell, how utterly impossible it is to try to tease out a coherent idea of how a Trump presidency will behave. To wit:

Trump and vice president candidate Mike Pence were introduced by former New York City Mayor Rudy Giuliani, a massive supporter and cheerleader of the Iraq War. Then during his speech, Trump spent a significant amount of time saying that did not support the Iraq War and was vocal about it as a citizen (evidence suggests that this is not actually true).

Having opposed the war, he nevertheless felt President Barack Obama and Secretary Hillary Clinton were wrong to have failed to establish a new agreement to keep more troops in Iraq (an agreement Obama inherited as president), and said that pulling troops out is what caused the rise of the Islamic State (ISIS). (evidence shows that Trump also had called for pulling out of Iraq previously while George W. Bush was still president)

He said the current administration's policy of "nation-buliding and regime change was a failure" and would end under his watch. But Trump also in this same speech criticized Obama's alleged "apology tour" during his administration that critiqued America's interventionism in other countries as "colonialism."

Regardless of the above statements, Trump said that he wanted America to "keep the oil" in Iraq, which couldn't have been done without many American troops staying in Iraq for a long time, which he maybe now supports. He actually said in his speech "To the victor, belongs the spoils" (I doubt Trump knows the origins of that quote at all, but it certainly makes for interesting reading). These are the kind of statements that make it clear that Trump is not by any means a "non-interventionist."

Trump pointed out that many countries where radical Islam has taken hold have terrible human rights records, but is in favor of using waterboarding "and more" as president to fight terrorism.

Trump wants to continue the drone strikes that frequently kill civilians and also wants more efforts to capture foreign combatants to try them at Guantanamo Bay, which he will keep open and operating.

Trump says "Political correctness has replaced common sense in our society," but also says that under his administration visitors to the country who "preach hate" will be asked to leave. Who will be deciding what that means?

Under that same contradictory attitude, Trump calls for an ideological test (he called it "extreme vetting") for immigrants that requires that they show that they "believe in our Constitution," which his general position on the First Amendment contradicts. Whose interpretation of the Constitution would this be?

Trump says he wants to build bridges and erase divisions in American society, but also wants to make a "commission" on radical Islam to identify the "warning signs" that somebody in America has become radicalized to be used by authorities and immigration, which is a thing that is already happening and hasn't always been terribly effective. He even pointed out in this same speech that in the case of both the Orlando shootings and the bombing of the Boston Marathon, the perpetrators had been previously interviewed by authorities.

Trump calls Obama a divider but hilariously seems to think that he is not and ended his speech by declaring a new spirit of "Americanism" will "heal our divisions" under his presidential administration, as though "healing" our culture plays any role in this election whatsoever.

Hillary Clinton's response to the speech was to tweet a reminder of all the former national security officials who oppose him. But, of course, Clinton is not exactly a peacenik, she's just the kind of warhawk the national security establishment likes.

Read the full transcript of Trump's speech here.