Those GOP presidential outsiders have mainly mainstream ideas

The staying power of the three outsider candidates in the Republican presidential race is supposed to signal voters' yearning for fresh, bold solutions to the nation's problems.

So what do Donald Trump, Carly Fiorina and Ben Carson have to offer that the conventional Republican candidates don't? The answer may surprise you.

On economic policy at least, the three outsiders are pretty much middle-of-the-road conservatives. With some notable exceptions, their views on taxes, trade, energy, health care, the minimum wage, immigration and regulation aren't markedly different from those of Jeb Bush, Marco Rubio and Chris Christie.

Take health care. Trump, Carson and Fiorina say they would repeal Obamacare because they abhor government interference in the health care market (though Trump has made favorable noises about single-payer systems in other countries). They would replace the law with vague, market-oriented alternatives. Their views closely parallel those of mainstreamers Bush, Rubio and Christie.

The two camps also overlap on energy and climate change. The outsiders would encourage more domestic crude oil production and roll back environmental regulations. They are all climate-change doubters: Carson says it's a distraction, Trump calls it a hoax and Fiorina wants to examine the science more closely. They all favor the Keystone pipeline, while Fiorina and Carson would also end subsidies for renewable energy.

Among the mainstreamers, Bush and Christie accept that humans are causing at least some climate change and that the U.S. has to take a lead role in negotiating cuts in carbon emissions with other countries. Rubio is less willing to accept that people contribute to global warming, yet agrees we all have a responsibility to protect the environment. All three mainstreamers, however, are as adamant as Trump, Carson and Fiorina about not imposing environmental rules that might crimp economic growth, cause job losses or reduce the ability of companies to compete abroad. Like the outsiders, the mainstreamers support the Keystone pipeline.

On taxes, both groups broadly agree that rates should be lower for most individuals and corporations. All six of them would simplify the tax code by collapsing income-tax brackets, lowering rates and eliminating deductions.

Fiorina would end all credits and deductions, then negotiate over the handful of tax breaks she would consider reinstating. The three mainstreamers would keep at least some deductions, for example, on charitable contributions (Bush and Christie) and interest on first-home mortgages (Christie).

One outsider (Trump) and one mainstreamer (Bush) would eliminate carried interest, the loophole that lets hedge fund managers pay lower taxes on performance fees. But they both supported the 2008 bank bailouts. And Christie alone is willing to take on AARP and other liberal interest groups in the entitlements lobby. He'd raise the retirement age to 69 from 67. And he wants to eliminate payroll taxes for those over 62 and under 21.

When it comes to taxes on individuals, Bush and Rubio are more centrist and focused on the impact on income inequality than the other candidates are. Bush would remove 15 million lower-income Americans from the tax rolls. He would pay for it by capping the deductions wealthy households can take. Rubio would put the top tax rate at 35 percent, down slightly from 39.6 percent now, but he'd enhance child tax credits.

Immigration is the area where Trump, Carson and to a lesser extent Fiorina supposedly stand out from the others. But that's based less on their policy prescriptions and more on their "build that wall" bombast. Trump goes furthest by seeking to deport undocumented immigrants and abolishing birthright citizenship, but even he agrees with Carson and Fiorina that immigrants with no criminal record should be allowed in as guest workers.

Bush would also let undocumented immigrants graduate to legal status, but he has backed off in giving them a path to citizenship, which he once endorsed. Rubio also once backed the citizenship route, but has abandoned that position in favor of calling for securing the border with Mexico for at least a decade before pursuing any immigration overhaul. Christie says he would track immigrants like FedEx packages and would prefer to crack down on employers who hire undocumented workers over building a wall.

Trade is the one issue where Trump and Carson stand more or less alone in calling for steep tariffs on imported goods, a position that would violate World Trade Organization rules and invite other countries to retaliate.

The voter coalition backing Trump, Fiorina and Carson might want to keep in mind that the candidates' economic policies — the ones that have the greatest impact on everyday lives — aren't outside the mainstream at all. The outsiders may decry the ineptitude of today's leaders, but their governing plans look mighty similar.