The US Chamber of Commerce tweeted: "Under Trump's trade plans, we would see higher prices, fewer jobs, and a weaker economy".
Where mainstream Republicans stand: There is some discord within the party on trade, but for the most part, Republican leaders and the interest groups that support them - such as the US Chamber of Commerce - think international trade agreements are, as my colleague Philip Bump wrote, "about the best possible way to 'create good jobs at home, help small businesses, expand consumer choices, and improve American competitiveness'."
Where Trump stands: Trump said today that he is "in favour, totally in favour of trade," but he has bashed every major free trade deal created or being negotiated in the past few decades.
In June, Trump said the Trans-Pacific Partnership trade deal, the one President Barack Obama is hoping congressional Republicans will help him finalise before he leaves office, "would be the death blow for American manufacturing".
He has also said he wants to "renegotiate" the North American Free Trade Agreement negotiated by Hillary Clinton's husband, Bill Clinton, which he said today "is a disaster. "And if we don't get a better deal, we'd walk away". His hesitation to support trade deals also arguably puts him to the left of Clinton, who has supported them in the past.
2 TAXING THE WEALTHY
Where mainstream Republicans stand: Tax breaks for the top income bracket - and for everyone, actually - that proponents say will mean more money flowing into the US economy in general. It's supply side economics 101.
Where Trump stands: Strain said Trump's tax plan was actually quite friendly to the wealthy, and today, Trump promised to cut the business tax. He also called for repealing the estate tax. Republicans say it is a burden on Americans, but Democrats say cutting or getting rid of it is a gimmick for the wealthy. The nonpartisan Centre on Budget and Policy Priorities says that only 0.2 per cent of estates would benefit from such a repeal.
But Trump's rhetoric - especially early on in the campaign - has sounded much less friendly to the 1 per cent. He's called high CEO pay "disgraceful". In his speech today, Trump said he'd be willing to close what's known as the carried-interest loophole that allows some hedge-fund managers and venture capitalists to pay a lower tax rate than average Americans.
"We will eliminate the carried-interest deduction and other special-interest loopholes that have been so good for Wall Street investors and for people like me but are unfair to American workers," he said.
3 THE DEFICIT
Where mainstream Republicans stand: Their laser-like attention on America's deficit has waned this election cycle (perhaps because it has decreased under Obama, though America still has record-level debt). But broadly speaking, Republicans say they make it a priority to not add to America's depleting bank account, while Democrats are less likely to stress that position.
Where Trump stands: Throughout his campaign, Trump has given minimal attention to the deficit. In fact, his tax plan would, in Strain's words, "explode" the deficit. (Though he wasn't the only GOP presidential candidate whose plan would have had that effect, Strain pointed out.)
4 ENTITLEMENTS
Where mainstream Republicans stand: Social Security and Medicare will bankrupt America, they say, and need to be drastically reformed. Before he was Speaker, Paul Ryan proposed making Medicare a voucher programme and reforming Social Security in a way that would have drastically reduced benefits for some.
Where Trump stands: Trump has publicly resisted the idea that entitlement benefits benefiting seniors need to be reduced. He was at his most vocal during the primary: "We're not going to cut your Social Security, and we're not cutting your Medicare. We're going to take jobs back from all these countries that are ripping us off, we're going to become a wealthy country again, and we're going to be able to save your Social Security. We're not taking it," he said at a December town hall in Iowa to a question from an AARP member.
5 INFRASTRUCTURE SPENDING
Where mainstream Republicans stand: Spending money to rebuild bridges and roads is generally not as big a priority for Republicans as it is for Democrats, Strain said.
Where Trump stands: Not unlike Democrats, Trump talks about it often. Trump said last week he would "at least double" Clinton's plan to spend money on new infrastructure, which would end up costing some US$500 billion.
6 TAX BREAKS FOR CHILDCARE
There's one tax break most Republicans aren't excited about - and Trump officially proposed it for the first time today. He wants to allow parents to deduct an unlimited amount spent on child-care expenses from their federal income tax.
The proposal is in keeping with Ivanka Trump's speech at the Republican National Convention that at times championed family policies that are more commonly found in the Democratic wheelhouse (albeit with a proposal that would largely benefit middle- and upper-middle-class families).
The child-care tax credit idea is "very much outside of mainstream Republican views." Strain said. "It's a massive, expensive programme for the middle class at a time when Republicans are trying to mitigate massive expensive programmes."
7 APPROACH IN GENERAL
Republicans think about the economy as a whole, said Strain, while Trump tends to focus his policies and messaging on specific industries, like manufacturing.
Taken as a whole, Trump's economic proposals are a mix of the right and left, with many on this list sounding more Democratic than Republican. What many of them are, above all, is populist.