Six dangerous issues in the 2016 GOP White House race
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Republican contenders for the White House are under pressure to toe the party line on a number of issues as they battle for the nomination.

Primary voters will demand to know where the presidential hopefuls stand on a slew of hot-button issues, including immigration, taxes and climate change.

Several of the candidates have already stumbled with their answers, highlighting the intense scrutiny they will be under in the critical early voting states of Iowa and New Hampshire.

Here are some of the biggest political landmines ahead for the Republican field.

IMMIGRATION

Immigration is one of the thorniest issues for the Republican Party.

In the GOP primary, the candidates are fighting for the support of mostly conservative voters, who are generally opposed to anything they view as granting “amnesty” to undocumented people.

But the eventual Republican nominee will need to make gains with Hispanic voters in the general election to win the White House, but that segment of the electorate has shifted decisively toward Democrats in recent years.

Sen. Marco RubioMarco Antonio RubioSenate Republicans tested on Trump support after Mueller Cuban negotiator says Trump's efforts to destabilize Cuba's government will fail Freedom to Compete Act would benefit many American workers MORE (R-Fla.), who helped write the Senate’s 2013 immigration reform bill, and former Florida Gov. Jeb Bush have cast themselves as candidates who can appeal to Hispanics and win the general election.

But to become their party’s nominee, both will have to overcome distrust on immigration from the party’s base.

Rubio has backed away from the reform legislation he helped write, telling a conservative crowd in February that border security must come first.

Other Republican candidates, such as Wisconsin Gov. Scott Walker and former Arkansas Gov. Mike Huckabee, have come out against a pathway to citizenship for undocumented immigrants. 

Bush has mostly stuck to his guns on granting illegal immigrants a path to citizenship, while emphasizing to conservatives their common ground on border security and fighting Obama’s executive actions.

Other candidates in the 2016 race, such as Sen. Ted CruzRafael (Ted) Edward CruzMJ Hegar announces Texas Senate bid Liberal survey: Sanders cruising, Buttigieg rising Overnight Defense: Trump ends sanctions waivers for buying Iranian oil | At least four Americans killed in Sri Lanka attacks | Sanders pushes for Yemen veto override vote MORE (R-Texas), are likely to hammer Rubio and Bush as backing “amnesty.”

COMMON CORE

The federal education standards known as Common Core are deeply unpopular in the GOP, with polls show that Republican voters oppose them by a 3 to 1 margin.

The education standards have provided a ripe target for Republican candidates to take swings at a top-down prescription from the federal government.

Sen. Rand PaulRandal (Rand) Howard PaulBooker, Harris have missed most Senate votes Trump vetoes measure ending US support for Saudi-led war in Yemen Bottom line MORE (Ky.) and Louisiana Gov. Bobby Jindal (R) have assailed the education protocol, with Paul’s PAC referring to it as “anti-American propaganda.”

Walker has said he wants to eliminate the requirement, and Gov. Chris Christie has created a commission to review its place in New Jersey.

Standing virtually alone in support of Common Core is Bush, who argues states have plenty of say in how the standards are carried out.

That stance could prove to be a real liability in Iowa. A February Des Moines Register poll found that while 56 percent of Iowans back the standards, just 34 percent of Iowa Republicans do.

THE IRAQ WAR

President George W. Bush’s controversial tenure in the White House looms large over the current field, and candidates have been rushing to distance themselves from his Iraq War.

It’s been hard to find a prominent Republican who now supports the 2002 invasion, which remains deeply unpopular with the public. Rubio, New Jersey Gov. Chris Christie and Cruz have all said that in hindsight, going to war was a mistake, as has Sen. Rand Paul (Ky.), a longtime critic of that military action.

The political peril of Iraq is especially acute for Jeb Bush, who struggled much of the past week to say whether he would have also authorized the military action. After vacillating on the issue for several days, Bush finally came out against his brother’s decision on Thursday.

But his confusing and dismissive responses to the question over several days gave his rivals an opening, with Paul arguing his responses made clear Jeb would be “George Bush 3.”

GAY MARRIAGE

Opposition to same-sex marriage used to be a reliable position for any Republican presidential candidate, but at a time of growing support for such unions, the GOP primary field has splintered.

Most Republican candidates have answered affirmatively when asked if they would attend a gay wedding. Walker said he actually has done so for a family member.

But social conservatives remain staunchly opposed to gay marriage, and some of the contenders are taking a hard line.

Former Sen. Rick Santorum (R-Pa.), Cruz and Jindal have fiercely opposed same-sex unions, and back legislative efforts to block them.

Others, like Paul, Rubio and Christie, have said the matter should be left up to the states. Rubio drew headlines in April when he said he did not believe sexual orientation was a choice, even as he said same-sex marriage is not a right.

The challenge of the issue was apparent when Ben Carson, the former neurosurgeon now running for the White House, apologized after saying that same-sex relationships in prison prove sexual orientation is a choice.

TAXES

Any Republican with an eye towards the White House is going to be talking taxes, which has long been one of the biggest dividing lines with the Democratic Party.

While all of the GOPers are eager to promote fiscal responsibility and tax cuts, there is an emerging split among the candidates on how far they are willing to go.

Some of the 2016 hopefuls have issued dramatic plans to slash taxes, as they look to stand out in the crowded field.

Cruz, Paul and Carson have called for the outright elimination of the Internal Revenue Service, and some are advocating a dramatic overhaul of the tax code, pushing for a single flat tax rate for all Americans.

Rubio has taken a different tack, proposing a tax plan in March alongside Sen. Mike LeeMichael (Mike) Shumway LeeGOP senator compares Mueller report's obstruction findings to 'Pinocchio' in 'Shrek 3' Dems sound alarm over top DOJ nominee Restore Pell Grant eligibility to people in prison MORE (R-Utah) that would moderately trim the top rates for individuals and businesses, while eliminating some deductions. But that proposal has opened him up to conservative criticism, as some on the right call it insufficient.

But Rubio is lockstep with nearly every other GOP candidate in signing Grover Norquist’s taxpayer pledge, vowing to oppose any and all tax increases while in office. The only Republican candidate thus far to refuse the pledge is Bush.

CLIMATE CHANGE

While none of the Republican contenders are vowing to tackle climate change if elected president, they are split on whether human activity is driving it.

Most Republican voters say it would be unacceptable for their candidate to believe in man-made climate change, let alone pursue policies to address it.

Some of the candidates, including Paul and Bush, have adopted an agnostic view, saying the jury is still out on how much the climate is changing, and if so, what role humans play in it.

Others, such as Cruz and Santorum, have depicted climate change as a hoax by the left to impose new environmental restrictions on the business community.

When the Senate considered legislation on the Keystone XL pipeline, Cruz, Rubio and Paul all voted for an amendment stating that climate change was real.

Paul was the only 2016 contender to support a separate amendment that stated human beings contribute to climate change.