Donald Trump taps into anger about U.S. misadventures in the world: Keith Boag

There are obvious problems with the foreign policy vision that Donald Trump outlinedWednesday, and we'll get to those.

But let's take a moment to admire what he has long understood about the Republican base that so many big-shot Republicans missed.

Trump knows that grassroots anger at American misadventures in the world was on the boil long before Barack Obama and Hillary Clinton arrived in the kitchen. The Republican base parted with its leadership on foreign policy years before, and his speech was tuned to that drift.

• Donald Trump vows in foreign policy speech to put 'America first'
• Trump slams NATO's 'free riders': Is that a message to Canada?
• Donald Trump calls Hillary Clinton 'crooked,' vows not to be 'too presidential'

Predictably, he took his swipes at "Obama-Clinton" and blamed them for the chunks of the world that are violently and despairingly messed up right now. But that's the sort of thing Republicans do even in their sleep.

Trump went further when he allowed his blanket condemnation of "foolish and arrogant" American foreign policy to fall across the Republican Bush-Cheney administration, as well.

He didn'tname them, but he certainly blamed them.

He dated the beginning of America's failures back to the end of the Cold War BushSr.and Clinton when "our foreign policy veered badly off course,"and then Trump quickly caught us up to the 21stcentury.

He identified the "mistakes" from "Iraq to Egypt to Libya" as having all begun with "the dangerous idea that we could make Western democracies out of countries that had no experience or interest in becoming a Western democracy."

And whose "dangerous idea" was that?

Bush Doctrine

It sounds a lot like what some people call The Bush Doctrine foreign policy based on a principle that regime change in a country such as Iraq would allow democracy to flourish, as though inside every Iraqi was an Athenian trying to get out.

Lest there be any doubt that he was talking about the Bush era, he reminded us: "I was totally against the war in Iraq, very proudly."

Just to be clear, his most explicit condemnations were still of Obama and Clinton. No apologies for them.

But Trump is astutely aware that when riding the Tea Party insurgency, it's sometimes more important to poke fingers in the eyes of the Republican establishment than it is to simply excoriate Democrats.

The Tea Party is nourished by its grievances with Obama, but it was born out of frustrations with Bush.

That might also be the reason Trump struggles to define a coherent foreign policy or any policy, really. He is continually reaching to satisfy every single one of the various passions of the populist wave he's surfing, and it just can't be done.

Played for a sucker

He wants Americanallies in the world to step up and take on more of the hard jobs instead of always relying on the U.S. a wink to those who think the country has been played for a sucker by its friends for too long and should step back from the game for a bitto see how they like that.

But he also says America's allies know they can no longer depend on the U.S. thanks to the weakness of Obama-Clinton and their shifting allegiances. That fits with his pitch that what's missing in the world is more purposeful American leadership.

But which of those does he believe is the real problem?

He sometimes fits the bill of an isolationist who wants to disengage with the world. He's the candidate of concrete and tariff walls at the borders. Even the distillation of his overarching philosophy into "America First" borrows the phrase from the isolationists of the 1940s.

But then his isolationist tendencies recede, and Trump conjures up the image of himself making geopolitical deals with Russia's Vladimir Putin.

There they are, world shapers, unblinking eye to unblinking eye, over a real life game of Risk that only Trump has the courage to walk away from if he must "because otherwise it becomes absolutely impossible to win."

The base loves the worldly strongman, too.

Part of the plan to "Make America Great Again" was always to restore American military strength by developing and buying the best technology available for whatever it costs. Nobody would dare to mess with a properly armed America. Peace through strength, etc.

But that should be the best clue of all that the various bits of the Trump plan don't all fit together so well.

In case you haven't been following along, Trump has so far promised to drive up defence spending, preserve social security and Medicare, balance the budget and cut taxes by an estimated $9.5 trillion over 10 years.

For some perspective, consider that the entire U.S. federal budget is about $3.8 trillion. Fiscal policy analysts question whether Trump could cut taxes, balance the budget and protect the social safety net even if heshut downthe entire Defence Department.

So there's that big hole in the overall plan.

But what Trump knows is that the most important gift he has is a talent for explaining the world in just the way that his supporters want to hear it explained; a talent for knowing what they want to believe and telling them it's so. Nothing else really matters.