Donald Trump and Paul Ryan, who met on Capitol Hill Thursday to work out their differences, are probably the two most important Republican figures since President Obama took office.
Ryan laid the intellectual groundwork for the House GOP majority that took over in 2010 and now leads it as speaker. Trump led a populist uprising that trampled on conservative dogma and now has taken over the party.
The conflict between the two has become the lead flashpoint in the GOP civil war over Trump's candidacy. Ryan has refused to endorse Trump and continued to do so on Thursday, despite some kind words.
"I was very encouraged with this meeting, but this is a process," he told reporters. "It takes a little time. You don't put it together in 45 minutes."
Much has been made of the philosophical differences between the two when it comes to policy. Ryan favors immigration reform with a path to citizenship, expanding free trade and cutting entitlements. Trump favors mass deportations, rails against trade deals and has promised not to touch Social Security and Medicare. Ryan has tried to tone down Republican rhetoric; Trump has dialed it up to 11.
It's not just that they have opposing views on their signature issues, however. The origin stories of how they rose to political superstardom are also completely reversed: One became famous for telling voters they had to make painful choices, the other became famous for telling them they could have it all.
Ryan was elected to the House in 1998, but he didn't become a household name among political junkies until early 2010 when he proposed a "Road Map For America's Future" that called for, among other things, privatizing Medicare and Medicaid and dramatically cutting benefits over time.
These are relatively common ideas on the right now, but at the time Ryan's proposal was a political wet blanket. Unemployment was peaking, deficits were spiking, Democrats were lined up behind an unpopular health care law and all Republicans had to do to win the House that November was stay quiet and let the inevitable backlash carry them to victory.
Running against the deficit was fine in theory, but Republicans like then-Senate candidate Carly Fiorina squirmed when pressed on specifics as to what they'd cut. The last thing Republicans wanted to do was open themselves up to attack with a sweeping overhaul of popular entitlement program, but entitlements accounted for two-thirds of spending, making their demands for a balanced budget sound ridiculous without touching the issue.
In the short term, Ryan was slow to catch on with Republican politicians, who mostly kept their distance. John Boehner, who was the GOP minority leader at the time, disavowed Ryan's plan immediately while politely thanking him for his hard work. Only a handful of Republicans signed on to co-sponsor Ryan's bill.
But along the way Ryan's plan became a rallying point for activists among GOP wonks and prominent conservative activists for naming actual cuts where previous Republicans had mumbled about reducing "waste, fraud and abuse" or knocking off minor budget items like public television subsidies that had minimal impact on the budget. Sarah Palin even suggested he should run for president.
When the GOP took over the House, leadership adopted a version of Ryan's plan with some of the rougher political edges sanded off as their rallying cry. By the time Ryan joined Mitt Romney on the 2012 GOP ticket, anti-tax crusader Grover Norquist had declared that the party's one goal was to elect someone"with enough working digits to handle a pen" and sign Ryan's plan into law.
Ryan's critics pointed out that his budget relied on gimmicks to make its math work and minimize the impact of its tax breaks for the rich. His subsequent budgets watered down its original savings to make them more politically palatable. But the basic legend behind Ryan remained the same: He rose to fame telling voters that they'd have to make actual tough decisions if they were serious about cutting spending.
Trump took a different route. He calculated that Republicans had misread their 2010 and 2014 gains as a sober-minded endorsement of Ryan's preferred policy approach. Instead, it was about angry voters upset with the economic crash and viscerally opposed to all things Obama.
Instead of asking people to accept painful choices, Trump promised no choices at all. Through the power of positive thinking, voters could have everything they wanted and more.
Trump proposed a massive $9.5 trillion tax cut while promising to increase military spending, invest in infrastructure, deport 11 million people, and protect Social Security and Medicare from cuts. When pressed how he'd pay for all of it, he falls back to the same "waste, fraud and abuse" platitudes that Ryan had rebelled against in 2010. It was enough to make a calculator cry.
In recent weeks, Trump hasn't even been consistent on whether a balanced budget is desirable, let alone achievable. Last month, he said he would somehow eliminate the entire national debt in eight years - Ryan's 2010 plan didn't even eliminate the deficit until 2063 - but a few days later he backed off and suggested it was a good time to borrow. This month he said deficits were not a concern because the U.S. could print more money or even force creditors to accept less than they were owed on treasury bonds, an idea experts across the spectrum warned could destroy the economy.
At the same time, the concessions to reality that Ryan made once in power to keep the government running while Democrats controlled the White House have antagonized conservatives, who increasingly view any deal with Democrats as a betrayal. Trump, happy to follow their anger, dumped on every Ryan-endorsed spending deal as a stab in the back. If only he had been in charge of negotiating, he would havegotten conservatives what they wanted, whatever that was.
Based on his performance in the primaries, Trump read the Republican base correctly. He's the presumptive nominee and the many Republicans who ran on Ryanism in some form or another are gone. Palin, who follows the base's id, no longer is talking up a Ryan presidential run - instead she's talking up a primary challenge to his House seat.
Ryan suggested on Thursday that the two might find "common ground" on policy.
Where that common ground is, though, is hard to see beyond a general opposition to Hillary Clinton and Ryan didn't offer much on this front. He name checked the Supreme Court and vague ideas like that "the Constitution, the separation of powers, the fact that we have an executive that has gone way beyond the boundaries of the Constitution," none of which Trump, who once said he would force military officials to commit war crimes before backing down, has shown any particular interest in. For Trump and Ryan, there can be no compromise when their core political identities are oil and water.
This article originally appeared on MSNBC.com.