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The Republican presidential candidates sound much alike in their zeal to shrink government, cut taxes and replace President Barack Obama's big health care law with, well, something entirely different. It takes some digging to see the distinctions.

That's when Mitt Romney, for example, emerges a few steps removed from the deeply conservative drift of the pack. Sure, he says constitutional abortion rights should be overturned. But unlike Michele Bachmann and some others, he's not up for clashing with the current Supreme Court over it. Yes, he wants to sweep away regulations that interfere with business. But unlike the slashers and burners, he wants the rules to be "updated and modern," not thrown as a heap in the trash.

Altogether, it's a familiar pattern on the cusp of party primaries. The candidates play to their ideological base so hard that true differences among them are blurred. The presumed favorite caters to the same crowd without getting locked into positions that might prove a disadvantage with the broader and more moderate electorate next fall.

That pattern results in an array of positions that sound good to the true believers but have little or no chance of becoming law. And it can produce flat-out contradictions.

Witness Herman Cain's assertions that no abortions should be allowed — and that the government has no business telling a woman she can't have one. Or the position of several candidates that gay marriage should be outlawed in the Constitution — and that states should be allowed to legalize or prohibit it individually, a right they would not have if the Constitution were so amended.

For all the me-too-isms of the campaign, some ideas stand well apart.

Cain is alone in bringing a national sales tax to the table with his catchy 9-9-9 plan to replace existing federal taxes with a 9 percent charge on personal income, businesses and purchases. Jon Huntsman wants federal authorities — yes, the ones empowered by all those regulations — to become even more aggressive on one aspect of the energy industry, breaking what he sees as an oil-company monopoly in the nation's fuel-distribution network to let natural gas compete more favorably.

And Ron Paul, ever the libertarian, proposes an evisceration of government and a disengagement from military obligations abroad that no others approach.

A look at a sampling of issues, what the candidates share and where they differ:

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Health Care:

They all want to try to repeal Obama's overhaul and most propose long-held GOP ideas to make insurance and care more affordable. Expansion of tax-advantaged medical savings accounts, limits on medical lawsuits and deregulation in the insurance industry to let policies be sold across state lines are common threads. None would require people to obtain health insurance, although Romney did just that as Massachusetts governor and Newt Gingrich once supported the idea.

Romney and Gingrich would, though, offer a measure of protection for sick people needing insurance, though neither goes as far on that front as Obama's law. They are among several candidates who would subsidize premiums through tax breaks or other means. No one lays out a fully developed plan marching the nation toward universal coverage; the priority is to get rid of "Obamacare." Paul proposes an unfettered free-market system that he hopes would see doctors treating the needy for free.

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Immigration:

Texas Gov. Rick Perry says the popular Republican campaign proposal to stretch a fence all along the 1,900-mile U.S.-Mexico border is "idiocy." He joins others in wanting more border agents. Most of the candidates say they support the fence, although some sound half-hearted about it. Huntsman, for one, says a fence might be needed but it "to some extent repulses me." The Republican field mostly opposes giving education benefits or other social services to the children of illegal immigrants; Perry defends Texas's record of doing so.

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Education:

Bachmann and Paul want to eliminate the Education Department; Gingrich and Rick Santorum would shrink it. Romney once supported closing the department but says he came to see the value of the federal government in "holding down the interests of the teachers' unions." The education overhaul of Republican President George W. Bush has no defenders in the field even though some supported it at the time.

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Regulations:

Cutting regulations is a core economic plank of the candidates, especially environmental and energy rules that might constrain development. Some would go further than others. Paul would get rid of most of them — along with nearly half the federal government. Like his rivals, Romney would seek the repeal of the law toughening financial-industry regulations after the meltdown in that sector. But: "We don't want to tell the world that Republicans are against all regulation. No, regulation is necessary to make a free market work. But it has to be updated and modern."

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Global warming:

Huntsman might be alone among the candidates in accepting the scientific evidence that humans contribute to global warming. Or, he might not be alone.

Romney declared earlier this year that "I believe the world is getting warmer, and I believe that humans have contributed to that." But he since said, "My view is that we don't know what's causing climate change on this planet."

Paul, too, has equivocated. In 2008, he said "human activity probably does play a role" in global warming and part of the solution should be to stop subsidizing the oil industry and let prices rise until the free market turns to alternate energy sources. Now he calls the science on manmade global warming a "hoax." That puts him in line with Cain ("poppycock"), Santorum ("junk science") and Perry ("scientific theory that has not been proven"), among others.

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Taxes:

Two optional flat taxes are in the mix: Perry proposes 20 percent on income for those who want an alternative to the current system; Gingrich proposes 15 percent. Both would preserve mortgage-interest and charitable deductions. Romney works within the existing tax code in proposing that no one with adjusted gross income under $200,000 should be taxed on interest, dividends or capital gains. Apart from Paul, who wants to eliminate the income tax and much of the government, no one has stepped further from the tax code than Cain with his 9 percent rates. Contenders agree that Bush-era tax cuts should continue to be extended, corporate taxes should be substantially lowered and the estate tax eliminated.

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Abortion:

Romney says: "I would live within the law, within the Constitution as I understand it, without creating a constitutional crisis. But I do believe Roe v. Wade should be reversed to allow states to make that decision." His bottom line appears to be that states should decide on the legality of abortion. That means the Supreme Court decision affirming abortion rights would have to be overturned by a future court made up of however many justices he could nominate and get confirmed as president. That position is a considerable step short of seeking a constitutional abortion ban, which would allow for no such leeway by the states. But his position on abortion has changed over the years and still does not seem set in stone.

Bachmann, in contrast, has strongly backed state "personhood" initiatives that, if made law, would almost certainly be confronted with a constitutional challenge and she has spoken of using other means, including federal legislation, to try to take on the status quo on abortion.

Perry, too, has modified his position. He now supports a constitutional abortion ban after saying states should decide their own laws on such issues.