Oil supplies are vast, but they’re unstable. And our politics is about to get more unstable, too. It all has the makings of a price spike, hurting consumers and benefiting Russia.

In a world inundated with cheap crude oil, and with storage spots filled almost to the brim, it might seem that long lines at the gas pump and high prices per gallon are history. But long lines and high prices may come back, in the new world of Trump-Putin geopolitics.

Trump the candidate vowed to “bomb the hell” out of oilfields controlled by ISIL. He called for stealing oil from other countries, later saying he meant to reimburse America for costs of its invasion of Iraq and other Middle East military actions. During the campaign he declared “I’m good at war in a certain way” and “I love war… including with nukes, yes, including with nukes.”

Whether that was Trump’s actual intent or just red meat for his base remains to be seen, but bellicose talk can lead to war—and war is very bad for continuity of oil supply.

Cheap hydrocarbons are not a pure good. They dampen demand for renewables like solar and wind that help slow climate change.

And, of course, oil is just one form of stored sunlight. Earth holds layer upon layer of natural gas, frozen methane, and the carbon rocks we call coal as well as the liquid gold we call oil.

Economist Ross McCracken, managing editor at Platts Energy Economist, says that even with large amounts of North American shale oil the world remains dependent for oil “on an unstable Middle East. There is enough oil in the world, but supply chains will remain dominated by the geology of the Middle East and the geography of demand.”

Adding to the global glut is Iran, which—with the lifting of sanctions—resumed legally exporting oil, something it did despite United Nations sanctions with help from offshore subsidiaries of ExxonMobil, whose CEO at the time, Rex Tillerson, is about to become Secretary of State.

In addition, the shrinking territory controlled by ISIL, which has been slowly but steadily degraded through both aerial bombing and unconventional warfare to assassinate its leaders, should mean more oil flowing from Iraqi wells even as civil war continues in neighboring Syria.

Such supplies, however, are inherently unstable, contributing to the global stability problem in the Trump-Putin era and kicking off a dangerous cycle in which unstable supplies contribute to unstable politics, which in turn, further destablize supply. “Geopolitical events have figured very large in questions about oil supply and I think that will continue,” says James Hamilton, professor of economics at the University of California, San Diego who studies the industry.

Some worry about a new American war in the Middle East, a development that could serve the political aims of both Trump and Putin, with collateral damage to your pocketbook.

Trump wants to show he is a tough guy who can quickly end “radical Islamic terrorism” as well as undo the global deal to let Iran openly return to world markets. Greater U.S. military activity in the Middle East, especially in light of Trump’s attacks on the Muslim faithful, would surely foster more hatred of America and its Western allies, encouraging more young people to turn to violence. The risk for Trump is that higher oil prices could turn off his voters unless they are persuaded that sacrificing more of their money for costly fuel is patriotic.

Putin would benefit from America getting into a Middle East war that disrupts oil supplies. Petroleum firms earn almost all of the profits of large Russian companies and higher oil prices should mean bigger profits for Russian oil, which would become a more important source of power, especially for Europe.

Putin needs higher oil prices because his weak and underperforming economy relies for hard currency almost exclusively on two exports: hydrocarbons and weapons. Hydrocarbons give him a lever over Germany and other industrial countries that need natural gas in winter. And war is, of course, beneficial to munitions makers. Many of the guns used to kill American soldiers in Iraq and Afghanistan were Russian made.

And the Middle East isn’t the only place where conflict creates oil issues. Civil wars and terrorist attacks on oilfields in Nigeria and North Africa also could disrupt oil supplies, says Herman T. Franssen, president of International Energy Associates, a consulting firm with deep ties in the Middle East and a former International Energy Agency chief economist.

What’s more, the drop in oil prices since 2014, as Saudi Arabia sought to maintain its share of the global oil market, is causing economic disruption in that country, a generous welfare state.

Many Americans may not realize it, but the United States was actually the world’s top crude oil producer last year and in 2015. One reason is the developing shale-oil industry, born of the last spike in oil prices. Shale oil is extracted with a technology known as fracking, in which solvents and sand are forced into soft underground rocks to unlock relatively small carbon deposits. Fracked wells account for more than 5 million barrels a day of American oil, about a third of U.S. production.

Owners of some existing shale oil wells in the Permian Basin of Texas can probably make a profit at $25 a barrel, Franssen says. Most other areas, however, need prices at or above $54 a barrel. The Saudi oil-price cuts were intended to make American shale oil uncompetitive. Instead they spurred advances in shale-oil drilling efficiency. Even though the number of working American oil rigs has fallen from about 2,000 to under 500 in the last two years, drilling didn’t decline by three-fourths. A modern rig can drill multiple wells by cutting through rock horizontally. Unused rigs are being cannibalized for parts, reducing costs.

Trump has said he wants to keep the U.S on top and shale oil will be part of that goal. Slashing regulations is a key part of his promises to voters and that likely will include issues around the environmental cost of fracking. Trump may run into opposition, though, as earthquakes like those bedeviling Oklahoma homeowners and other damage from fracking sours some voters. Other environmental problems, such as aging, leaky oil pipelines, could also come into play.

The U.S. extracted domestic crude at the rate of 15 million barrels per day in 2015, the federal Energy Information Administration estimated. Saudi Arabia was second at nearly 12 million barrels; Russia was next at 11 million barrels; and China, fourth, at just under 5 million barrels per day.
Proven oil reserves—meaning the amount of crude in the ground that companies count as assets because it can be pulled from beneath the surface—will provide enough carbon fuel to meet the expected world demand through 2040, the federal Energy Information Administration estimated in its most recent annual energy outlook report.

That does not mean the world will run dry in 24 years. Proven reserves is an accounting measure, not a geological measure. It does not include oil yet to be discovered, oil that cannot be profitably extracted with current technology or at current prices, and other factors. That measure tells us, however, that at current world prices oil will be cheap for a very long time assuming relative peace continues.

Cheap oil is decidedly not in the interests of Russia or of those Middle East and African countries run by autocrats, dictators and kings who need oil profits to mollify their subjects and stay in power.

A major disruption of Middle East oil supplies still might not raise oil prices enough to help Russia deal with its limp economy. Trump has vowed to ease regulations so that America extracts more oil than it needs and remains the top producer. So Americans might enjoy cheap gasoline even as Europeans struggle to find enough Middle East oil to fill the tanks of their fuel-efficient cars and are forced to pay higher prices for Russian oil.

An unstable Saudi Arabia—and instability among its oil-rich neighbors—may also foster more hatred or American and the West. That, too, could lead to wars and revolutions, adding to uncertainty about oil supplies and who will control them.

So, while today oil is abundant both under the surface and in storage, that can change fast. And both Donald Trump and the leader for whom he keeps expressing his admiration, Vladimir Putin, have interests that just may come together in ways that may mean more war together with an end to cheap and reliable oil.