Chris Christie
New Jersey Gov. Chris Christie has either changed or not given his complete positions on divisive issues such as vaccination, immigration, gun control and the Common Core State Standards Initiative. Above, Christie appears during a press conference at 7 World Trade Center in New York Sept. 24, 2014. Getty Images/Bryan Thomas

WASHINGTON -- As the governor of New Jersey, Chris Christie has largely stayed out of the national political fray. He was too busy running his state, Christie would often reply when asked about divisive issues such as access to contraceptives or immigration.

When the U.S. Supreme Court decided to allow Hobby Lobby to opt out of the Affordable Care Act’s contraceptive mandate last summer, Christie -- unlike the rest of the Republican Party’s probable 2016 field of U.S. presidential candidates -- opted to say nothing about the ruling. “The point is: Why should I give an opinion as to whether they were right or wrong?” Christie said on CNBC’s “Squawk Box.” “At the end of the day, they did what they did. That’s now the law of the land, unless people in the legislative branch try to change it.” Questioned in 2012 whether he personally agreed with evolution, Christie answered, “None of your business.”

But now as Christie launches a presidential bid, his ability to take a pass on addressing issues subject to national debate is going to get tested, a lot. Presidential candidates are rarely allowed to remain focused on a singular issue: The process is more like a series of comprehensive interviews than the submission of a resume. And when presidential candidates take a pass on an issue, their opponents and the press tend to pounce.

Christie has also opted to shift his positions on a number of issues, by offering statements in support one approach -- such as a pathway to citizenship for illegal immigrants -- and then changing his mind. With a history encompassing a pivot on vaccines and a sudden embrace of expanded gun access in New Jersey, the candidate will be forced to clarify where he stands on a number of issues.

Chicago Demonstration, Chris Christie, July 25, 2014
Demonstrators protest outside a Hilton hotel where New Jersey Gov. Chris Christie was attending a fundraiser for Illinois Republican gubernatorial candidate Bruce Rauner in Chicago July 25, 2014. About 100 people opposed to Christie’s and Rauner’s stances on gun control, public-employee pensions and other issues chanted and made speeches outside the hotel during the fundraiser. Scott Olson/Getty Images

Gun Control

In considering which candidate to back in the Republican primary-election field, gun control can be a deal breaker for many voters. And Christie comes from a state with some of the country’s strictest regulations on gun ownership. It is virtually impossible for the average New Jerseyan to obtain a concealed-weapons permit. And, during his time in office, Christie has done little to change those rules, pointing to the state Legislature as being responsible for modifying the laws. In April, he called for “the right balance” on gun control.

But in a clear sign that Christie recognizes gun control could be a big issue during primary season, the governor on Monday night at 9:30 p.m. EDT -- less than 14 hours before his presidential-campaign launch -- instructed the state to make it easier for victims of domestic violence to obtain a firearm in New Jersey, an issue that gun advocates had been strongly pushing.

Immigration

Christie has spent much of his time in office avoiding the issue of immigration. It appears he has had good reason, as it’s a topic that has deeply divided Republicans. And it’s one that many pundits have said could derail the general-election hopes of the GOP.

Initially, Christie backed a pathway to citizenship. But that view has become untenable among many Republicans, who call it amnesty as they make an effort to stamp out any of its supporters in the party. In May, Christie shifted his position, saying he no longer backs that pathway. “I think I’ve learned over time about this issue and done a lot more work on it,” he told Fox News’ Megyn Kelly. “Back in 2010, I was in my first couple months as governor. I’ve now learned some of the ramifications for all these things.”

There are still a lot of blanks for Christie to fill in on the issue of immigration. And, since it will be such a hotly contested issue during primary season, there will be many waiting to hear a more lengthy explanation of his views.

Vaccination

In February, Christie took an ill-fated trip to Europe where he was asked, among other things, to weigh in on the growing national debate around vaccines. An outbreak of measles at a California amusement park had riled up both sides in the dispute over whether the government should force parents to vaccinate their children.

Christie at first voiced sympathy for parents who are anti-vaccination. “Mary Pat and I have had our children vaccinated, and we think that it’s an important part of being sure we protect their health and the public health,” Christie said while in London. “I also understand that parents need to have some measure of choice in things as well, so that’s the balance that the government has to decide.”

At an event in New Hampshire a month later, however, Christie said he isn’t behind voluntary vaccinations. “I would err on the side of protecting public health through vaccine unless that vaccine has proven to be harmful to the public,” he said.

Common Core State Standards Initiative

The educational standards that a number of states designed and then spread across the country are among the most heated topics in the presidential campaign. Christie has already entered the Common Core debate -- and delivered a flip-flop, according to the fact-checking PolitiFact.

New Jersey enacted the Common Core standards after Christie took office in 2010. And he defended them along the way. “We’re doing Common Core in New Jersey, and we’re going to continue. And this is one of those areas where I’ve agreed more with the president than not,” ABC News quoted him as saying in 2013. And he criticized politicians who opposed them for putting politics above progress. “Part of the problem in Congress right now, on both sides of the aisle, is that folks care more about their primaries than they care about anything else,” he said.

In May of this year, however, Christie announced he was reversing that decision. “It’s now been five years since Common Core was adopted. And the truth is that it’s simply not working,” he said in making the announcement about the reversal. “It has brought only confusion and frustration to our parents. And has brought distance between our teachers and the communities where they work.”