Sen. Rand Paul, R-Ky., told ABC News' Jonathan Karl he believes "all options should be on the table" to prevent a nuclear Iran, but the U.S. should not immediately accept the idea of war when the threat of a nuclear Iran could be contained as it has been with other nuclear powers.

"I've repeatedly voted for sanctions against Iran. And I think all options should be on the table to prevent them from having nuclear weapons," Paul said on "This Week" Sunday. But he said those who oppose the idea of containment - or living with an Iran with nuclear weapons - ignore that such an outcome has been necessary in the past.

"They said containment will never ever, ever be our policy," Paul said of those who oppose Iran getting nuclear weapons at any cost. "We woke up one day and Pakistan had nuclear weapons. If that would have been our policy toward Pakistan, we would be at war with Pakistan. We woke up one day and China had nuclear weapons. We woke up one day and Russia had them."

"The people who say 'by golly, we will never stand for that,' they are voting for war," he added.

Asked by ABC's Karl if we could "live with" and "contain" a nuclear Iran, Paul said, "I think it's not a good idea to announce that in advance."

"Should I announce to Iran, 'Well, we don't want you to, but we'll live with it?' No, that's a dumb idea to say that you're going to live with it," Paul said. "However, the opposite is a dumb idea too," referring to the prospect of war.

Paul also defended his push to cut U.S. defense spending beyond lower sequester levels.

"I believe national defense is the most important thing we do, but it isn't a blank check," he said. "Some conservatives think, 'Oh, give them whatever they want and that everything is for our soldiers' and they play up this patriotism that, 'Oh, we don't have to control defense spending.'"

"We can't be a trillion dollars in the hole every year," he continued.

2016 and the GOP

Sen. Paul joined ABC News on the trail Friday near Manchester, New Hampshire, where he traveled for the conservative Freedom Summit this weekend, which featured several GOP leaders considering 2016 presidential bids. Paul, who has climbed to the top of the 2016 field, weighed in on the future of the Republican Party, fellow Republican Jeb Bush's recent remarks on immigration, and his own potential presidential candidacy.

Despite winning several recent straw polls, and leading the Republican field in a new CNN poll on 2016, Paul is still shying away from being labeled the GOP frontrunner.

"I don't know if that's good luck or bad luck. So why don't we not go there?" Paul said. "I guess it's better than not being noticed."

He may be ambiguous about his candidacy, but Paul is adamant on his views about the Republican party and its future.

"No matter what happens, I think the Republican Party needs to evolve, change, grow if we're going to win again," Paul said. "And so I do want to be part of that."

He has recently focused his efforts on bringing in minorities and young voters who gravitate toward Democrats. The senator has visited Berkeley, Howard University, and Detroit, working to bring new communities into the Republican fold. Paul said his party's staunch and sometimes alienating policies face "a hardened resistance."

"It's been going on for decade after decade after decade. So it's not going to be easy to change," Paul said of winning over young and minority voters. "We got three percent of the vote in Detroit. There's not one Democrat that's offered to help the people in Detroit. I offered them a billion dollars of their own money to try to help them recover."

But when asked by Karl to explain how those tax cuts he is proposing would help them, Paul said it would allow businesses to hire the unemployed.

"That money will be left in the hands of businesses that people in Detroit are already voting on," he said. "Let's grow those businesses and they will employ more people."

Jeb Bush and Immigration

Earlier this week, another conservative superstar, former Florida Gov. Jeb Bush, made headlines with his comments on immigration, saying that while illegal immigrants break the law by crossing the border, "it's not a felony, it's an act of love."

While Paul didn't dispute Bush's comments, he did say he may have framed them differently.

"If it were me, what I would have said is, people who seek the American dream are not bad people."

"But here's the way I'd finish up," he added. "We can't invite the whole world. When you say they're doing an act of love and you don't follow it up with but we have to control the border, people think, well, because they're doing this for kind reasons, that the whole world can come to our country."

While Bush may be a rival to Paul in a potential 2016 GOP race, the Kentucky senator's wife may hold the deciding vote on whether he runs, which he will decide on after the 2014 midterm elections.

As of now, "There's two votes and at least one undecided in the house," Paul said. "So we'll see."

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