Sen. Rand Paul, (R-Ky.), a potential White House contender in 2016, is known for his belief in limited government. Here his take on Obamacare, the Constitution and more, in his own words. (Julie Percha/The Washington Post)

When the presidential buzz began building around Sen. Rand Paul (R-Ky.) a couple of years ago, the expectation was that his libertarian ideas could make him the most unusual and intriguing voice among the major contenders in the 2016 field.

But now, as he prepares to make his formal announcement Tuesday, Paul is a candidate who has turned fuzzy, having trimmed his positions and rhetoric so much that it’s unclear what kind of Republican he will present himself as when he takes the stage.

“He’s going to get his moment in the sun,” said David Adams, who served as campaign chairman for Paul’s insurgent 2010 Senate campaign. “What he does with it from there will have bearing on the Republican Party.”

There are at least two areas where Paul has moved more in line with the conservative Republican base, somewhat to the consternation of the purists in the libertarian movement: adopting a more muscular posture on defense and foreign policy, and courting the religious right.

Where he once pledged to sharply cut the Pentagon’s budget, for instance, Paul late last month proposed a $190 billion increase over the next two years — albeit one that would be paid for by cutting foreign aid and other government programs. His tour following the announcement of his candidacy will include an event at Patriots Point in South Carolina’s Charleston Harbor, with the World War II-era aircraft carrier USS Yorktown as a backdrop.

With an optimistic speech surmising that "America's best days are ahead of us," Sen. Rand Paul (R-Ky.) garnered big applause and chants of "President Paul" at the 2015 Conservative Political Action Conference. (AP)

The haziness over Paul’s positions increased last week with his conspicuous silence on controversies in the realms of both national security and the cultural fronts.

Nearly all of his potential rivals for the 2016 GOP nomination have been vocal in their support for Indiana’s new religious liberties law, which critics say would allow discrimination against gays. And the Republican response to President Obama’s nuclear negotiations with Iran has been widespread skepticism.

In both instances, Paul’s office said he was vacationing with his family and would not comment.

What Paul says Tuesday and in several stops in the following days will be closely watched by a handful of disparate constituencies into which he has tried to make inroads over the past year, including Silicon Valley executives drawn to his libertarian ways and more traditional Republican business leaders who are wary of them. Attracted to his promise of expanding the GOP electorate, they have met with Paul, but many remain unsure of his electability, as well as his views.

“He’s still the same guy. It’s only how he’s viewed that has changed,” Adams said. “He’s gone from somebody viewed as an oddity to somebody who’s interesting. And on the issues, he has answered the same questions over and over, that he hasn’t so much changed but shown a more three-dimensional side of where he’s coming from.”

Paul also has been trying to find common cause with evangelical Christian voters, who have been skeptical of and even hostile toward the energized libertarian element of the GOP.

“The First Amendment says keep government out of religion. It doesn’t say keep religion out of government,” he told a group of pastors at a private breakfast on Capitol Hill on March 26.

His tone was a signal, wrote David Brody of the Christian Broadcasting Network, that “this is not some ‘crazy libertarian’ who wants to distance himself from faith-and-government issues.”

[ 7 things to know about Rand Paul ]

Paul has tried to reach out to African American voters as well with visits to historically black colleges, including a stop last month at Bowie State University in Maryland. While some conservatives have cheered his efforts and his calls for criminal-justice reform, others say he has not connected.

“I found him superficial,” said Bob Woodson, president of the Center for Neighborhood Enterprise, who met privately with Paul on Capitol Hill a few months ago. “I think these guys have got to do more than show up. Going to Howard [University] and then going to Ferguson [Missouri]? I don’t know what that was all about. His talk about the militarization of police felt like pandering.”

It is a tricky and delicate balancing act that the senator from Kentucky is trying to pull off: finding a way to make himself more acceptable to conservatives without dampening the enthusiasm of the boisterous, youthful and well-organized grass-roots network that his father, former congressman Ron Paul (R-Tex.), ignited in presidential bids in 2008 and 2012.

“Rand has made it clear that his strategy is to embrace a broader group of Republicans than his dad captured,” said Drew Ivers, Ron Paul’s 2012 Iowa campaign chairman. “Whether he can pull it off has yet to be proven, and he has significant challenges, even though he’s a smart guy and capable.”

“The question is mathematics: How many people will he gain versus how many will he lose, both in terms of numbers and energy?” said Ivers, who says he plans to stay on the sidelines this time around. “I’d prefer if he had a different strategy, reaching out his arms to the center-right and saying ‘join me,’ rather than meeting them in the middle.”

Nick Gillespie, editor in chief of the libertarian magazine Reason, agreed: “To the extent he sounds more like every conservative Republican, he sounds less interesting to libertarians. I don’t see what he picks up by being a version of Ted Cruz or Marco Rubio,” two other freshman senators who are in the mix for the Republican nomination for 2016.

Then again, Gillespie added, “he’s not a doctrinaire libertarian. He’s libertarian-ish. He’s not his father.”

Rand Paul’s spokesman, Sergio Gor, said the senator appreciates the support from his father’s ­coalition and continues to draw Ron Paul backers.

“Rand Paul and his father each attract new people to the party in their own unique ways, yet they both share a deep passion for liberty,” Gor said by e-mail. “Among the thousands of people Sen. Paul meets every month, the most enthused and energetic are usually those individuals who supported his father. The same individuals continue to stand with Rand.”

Rand Paul is also adjusting to changes in the overall political climate, particularly on foreign policy.

Coming out of the GOP’s 2012 electoral defeat, it appeared that many Republicans had grown weary of war and were anxious to shake the George W. Bush brand of interventionist foreign policy. But that was before the rise of the Islamic State organization, with the horrific videos of hostage beheadings, and the descent of much of the Middle East into ­chaos.

Now, the more hawkish forces in the party are again taking the lead. And Paul’s noninterventionist rhetoric is being tempered by declarations such as the one he made at the Conservative Political Action Conference in February that his priority would be “a national defense unparalleled, undefeated and unencumbered by nation-building.” (For the third year in a row, Paul won CPAC’s presidential straw poll.)

Paul’s statements playing down the threat of a nuclear Iran have put him at odds with conservative Republicans in the past. More ­recently, he angered non­interventionists when he joined 46 other Republican senators in signing a controversial letter, authored by Sen. Tom Cotton (R-Ark.), telling Iran’s leaders that any nuclear deal would not be binding past the end of the Obama presidency if it were not agreed to by Congress.

Former House speaker Newt Gingrich, who won the South Carolina Republican primary in 2012, said that the message Paul will send with his event at Patriots Point is unmistakable: “He’s announcing in a place of military strength, and probably will be talking about our need to remain strong.”

Gingrich added: “I don’t think that’s political calculus. I think that’s reacting to the real world.”

Others are more skeptical about the shift.

“That’s what you call walking something back in a fast way,” said former South Carolina Republican Party chairman Katon Dawson, who is supporting former Texas governor Rick Perry. “Let me tell you: He’s got a lot of explaining to do.”

If Paul can find the sweet spot, making peace with the Republican base while maintaining his libertarian cred, the campaign calendar will give him some built-in advantages in a crowded GOP field.

Of the first four state contests, two — Iowa and Nevada — are caucuses, where his prospects will be boosted by the energy and organizing power of the libertarian grass-roots network. And New Hampshire, whose official motto is “Live Free or Die,” is known for its antipathy to heavy-handed government.

“This thing is front-loaded. The advantage goes to those that have an apparatus in place. Rand has an apparatus in place. He inherited that,” said David Lane, a conservative Christian leader who has organized an effort to encourage evangelical pastors to become more politically active.

But how transferable are those loyalties in the face of what many Ron Paul supporters see as apostasies?

“He is upsetting a lot of the more purist libertarians of his father’s base. I see the rage all the time in my Facebook feed,” said Rachel Mills, a former press secretary to Ron Paul who was campaign manager for Sean Haugh, the Libertarian Party’s 2014 Senate nominee in North Carolina.

But she predicted, “When he really gets started, all of us are going to be surprised with how much of the smart libertarian base is going to be there for him and really have his back.”