President Donald Trump's pick for national security advisor signals a willingness by the administration to take a more aggressive stand against U.S. adversaries like Iran or Venezuela —and that could mean higher oil prices in the very near future.

Analysts said the appointment of John Bolton, former U.N. ambassador, makes it even more likely that the Trump administration will withdraw from the Iran nuclear deal when it is up for review in May, and tensions could ramp up against the Middle Eastern country. Bolton succeeds H.R. McMaster, who resigned.

"I can't think of a more hawkish appointment than John Bolton," said Helima Croft, global head of commodity strategy at RBC. "He's a powerful advocate for a confrontational approach."

Croft also said the appointment appears to leave Defense Secretary James Mattis as the only one representing a moderate foreign policy at this point. "Are the Iranians seeing the writing on the wall? Will they curb their activities? His appointment should put the fear of God in them, but who knows."

Bolton has advocated for pre-emptive action against both Iran and North Korea because of their nuclear programs. His first act may be to successfully encourage Trump to end the Iran nuclear deal, struck with Iran by the U.S., some members of the European Union and other countries as a way to curb its nuclear program in return for ending sanctions on the country, including its oil.

Mattis and former Secretary of State Rex Tillerson had been reluctant to abandon the Iran deal, which also included China and Russia. Further financial sanctions against the country have also been discussed.

Venezuela's economic crisis is complicating matters and damaging its energy production capabilities. Venezuelan President Nicolas Maduro is running for re-election despite the objections of the U.S. and other countries that the election is unfair. Venezuelan oil already is coming off the market, and could continue to decline as the country's energy infrastructure deteriorates.

"Even if it's just additional sanctions on Iran, that could hurt investment in the country and reduce flows of their oil. The market would really miss their oil this time around because of Venezuela," said John Kilduff of Again Capital. "Because of Iran's advanced ballistic missile capabilities, the other countries have offered additional sanctions to try to keep Trump in the nuclear pact."

Oil prices were higher Friday, with West Texas Intermediate futures trading over $65, a nearly 2 percent gain. Gold, benefiting Friday from fears about trade wars, could also gain if the U.S. becomes more aggressive, not just with Iran but others like Venezuela or North Korea. Gold futures for April rose 1.5 percent Friday, to $1,347 per ounce.

Croft said May will be important for oil prices, with the Iran deal up for renewal May 12 and the Venezuela election on May 20. "If they go forward with those elections, we could see much more coercive economic policies toward Venezuela. That's when the oil market might start paying attention," she said.

"The oil market is underappreciating the importance of the personnel changes," she added. "They're underpricing the personnel changes."

Global oil demand has been improving and the pact between OPEC and Russia has helped steady prices and send them higher. Growing U.S. production from shale fields like the Permian Basin has added supply while Russia and Saudi Arabia have reduced theirs.

Kilduff said geopolitical tensions have moved prices higher recently, including anti-Iranian comments from Saudi Crown Prince Mohammed Bin Salman, who said that if Iran develops a nuclear weapon, so will Saudi Arabia.

In an interview on CBS' "60 Minutes," the prince also compared Iran's supreme leader, Ayatollah Khamenei, to Adolph Hitler. The prince is currently in the U.S., and met with Trump earlier this week.

Saudi Arabia and Iran are engaged in a proxy war in Yemen, and are at odds on Syria, which Iran has supported.

Croft said if the U.S. drops out of the nuclear deal it could take an even harsher posture toward Iran. "The question is, are we talking about efforts to economically isolate Iran, or are we talking about efforts to change the regime?" she said. "This is where the Permian makes things different. If this had been 2010, oil would be much higher. There's a view that U.S. short cycle oil makes a difference. We could just make up for anything."

But Croft doesn't see proof that U.S. shale could make up for a shortfall in the world market.

"I haven't gotten any evidence," she said. "I don't see any signs that OPEC is going to be quick to rush in and save things." She said with the changes in Washington, it's possible there could be 200,000 to 300,000 Iranian barrels off the market by the fourth quarter, and Venezuelan production losses could total 1 million barrels.

Bolton served in the Reagan administration, and President George W. Bush named him undersecretary of state for arms control and international security. Bush also appointed him as his representative to the U.N., which Bolton called irrelevant. Ultimately, Congress blocked his confirmation and he had to step down from that role.

"Bolton is the hawk's hawk," wrote Cliff Kupchan, chairman of Eurasia Group. He noted that besides pushing for pre-emptive strikes on North Korea's nuclear program, he has criticized the planned Trump-Kim Jong Un summit as useless.

"He's a fierce opponent of the Iran nuclear deal. In 2015, before the deal, Bolton penned an op-ed titled 'To Stop Iran's Bomb, Bomb Iran.' Bolton's appointment will likely make US policy on both hot-button issues more hardline," added Kupchan. "At least on the margins, the chance of a strike on North Korea goes up, of successful US-North Korea diplomacy goes down, and the Iran deal is in even more trouble."