WASHINGTON, DC — A presidential campaign throws policy differences into stark relief and so it is this time, on immigration, spending, trade, foreign affairs — you name it.

In this cockeyed campaign year, though, the divide at the moment is between the country’s top two Republicans: the presumptive presidential nominee Donald Trump and House Speaker Paul Ryan, a conspicuous holdout from the candidate’s bandwagon and a man once denounced by Trump for producing a “death wish” budget.

Trump the businessman’s “art of the deal” may get its first big test in the political world at an expected meeting next week with the speaker aimed at some version of common ground. It will bring together a sober, policy-driven, consensus-seeking conservative and a crowd-rousing improviser with indistinct ideology and a handful of core issues, several of them combustible.

Here are some of the contours of the chasm between them :

SPENDING

In December, after Ryan negotiated a plan to ease automatic spending curbs on the Pentagon and domestic agencies, Trump blasted him and other GOP leaders, saying “the elected Republicans in Congress threw in the towel and showed absolutely no budget discipline.”

Trump presents himself as a guardian of Social Security and Medicare even as other Republicans, Ryan chief among them, see no choice but to restrain their cost. “He represented cutting entitlements,” Trump said this year, recalling Ryan as Mitt Romney’s running mate in 2012. “That was the end of the campaign. I said, ‘you’ve got to be kidding.'”

Trump says he can save Social Security by growing the economy, with no increases in the retirement age and or other scale-backs, a contention disputed by many economists.

In Trump’s view, Ryan hasn’t done right by the country for some years. As a budget leader before he became speaker, Ryan was the driving force behind attempts to control the debt, a mission he still embodies. His 2011 budget plan, heavy with spending cuts and a Medicare overhaul, earned Trump’s scorn. “If anyone needs more evidence of why the American people are suffering at the hands of their own government, look no further than the budget deal announced by Speaker Ryan,” he said at the time.

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TRADE

Ryan is a leading advocate for free trade and his support for deals negotiated by the Obama administration with Pacific nations and other partners is distinctly at odds with Trump’s vow to dismantle or renegotiate such agreements.

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IMMIGRATION AND ISLAM

Silent on the Republican presidential race for much of it, Ryan was moved to speak out when Trump proposed banning foreign Muslims from entering the U.S. until the security of Americans could be assured.

“Freedom of religion is a fundamental constitutional principle; it is a founding principle of this country,” Ryan said in response. Trump’s plan “is not what this party stands for, and more importantly it’s not what this country stands for.”

More broadly, Ryan embraced a path to legal status for people in the country illegally, stepping back from previous support for “a path to earned citizenship.” He’s said he could not imagine how Trump could achieve his plan for the mass deportation of the 11 million people in the country illegally, then the re-entry of the “good ones” through a “giant door” in his Mexico border wall.

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AMERICA ABROAD

Ryan supports an activist foreign policy, not a “fortress America,” while Trump’s “America First” campaign suggests a retrenchment and a questionable commitment to traditional allies. Ryan has dismissed the notion the U.S. could retreat, as reflected by Trump’s demand that allies pay more or America will step back from protecting them.

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PLANNED PARENTOOD

Ryan has supported stripping federal money from Planned Parenthood because of its abortion services. Trump, while criticizing those abortion practices, said the organization does good work for women on other fronts and those parts of its mission should continue to get federal money. He later qualified the remark to suggest the group should not get federal support as long as it provides abortions, while reaffirming his view that “Planned Parenthood has done very good work for millions of women.”

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HILLARY CLINTON

On some issues, each is closer to Hillary Clinton than to each other. But their common wish to deny her the White House will be a key reason they come together, if they do.

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Associated Press writers Jill Colvin and Andrew Taylor contributed to this report.