Tens of millions of people died in World War I and World War II as nations fought over resources, territory and ideology. But in the 21st century, economic and cyber-warfare between warring countries have largely replaced tanks, bombers and troops.
As tensions continue to ratchet up between Russia and Ukraine over the province of Crimea, could this sort of bloodless conflict be one possible outcome? Experts say it's possible.
"Nowadays it's hard to separate warfare from cyberwarfare, or even economic warfare," said Jacques Gansler, a former Pentagon undersecretary for technology and security, now professor of public policy and private enterprise at the University of Maryland. "The three are interrelated."
Gansler says that Ukraine is important to Russia for economic, rather than security reasons. It represents an important economic buffer between Russia's zone of influence and Europe. While observers say that Russia has already dispatched unmarked troops into Crimea, it's not clear whether a shooting war will break out.
Moscow has already engaged in cyber-warfare, launching denial of service attacks against Estonian government websites in 2007, and Georgia in 2008 before attacking that nation. Both nations were satellites of the former Soviet Union, along with Ukraine.
Cyber-attacks are "bound to be part of any future engagements," Gansler said. "We also have economic concerns about cyber having impact on industry or messing up power grids or communications systems. These are the things we are worrying about for the 21st century."
The opening salvos of a cyber-war between Russia and Ukraine may have already begun. Ukrainian parliament members said this week that their cell phone and Internet services are being blocked by Russian agents in the Crimea.
Crimea has only one Internet exchange point that controls access to all traffic within the disputed territory. Russia also controls three of the six Internet junctions into the entire nation of Ukraine.
Crippling a nation's digital infrastructure could be as important as seizing telegraph lines, railroads and radio stations was for enemy armies during World War II. Today, water, power and energy supplies are digitally linked and could be vulnerable to hacker attacks or viruses, such as the Stuxnet worm that damaged one of Iran's nuclear facilities and was reportedly devised by Israeli and American programmers.
U.S. officials have also blamed China for infiltrating U.S. public water supplies and power grids, although there has been no damage so far.
Given today's global economy, any disruption through a shooting war could hurt the victor, as well as the victim. One historian notes that Nazi Germany wanted a "large economic space" of nations around it to feed the German economy. For Adolf Hitler, the Ukraine was a vital agricultural area -- "the breadbasket of Russia" -- as well a gateway to the oil fields of the Caucuses region.
Today, controlling the Ukraine is part of Vladimir Putin's plan to build his own "Eurasian Union" to rival the existing European Union, according to Jan De Vries, a professor at the University of California, Berkeley, who specializes in the economic history of Europe.
"The main economic strategy of the Putin regime in Moscow is to recreate a zone more or less on the borders of the old Soviet Union which, if it cannot be a single state, it can be a single economic zone ruled by a customs union," De Vries said.
De Vries says that the idea of Ukraine joining the European Union doesn't appear to be a threat, unless you are living in Moscow. That threatened economic perspective may explain Putin's actions in Crimea.
"Today, when we look at the European Union, it seems a benign, useful and admirable institution," De Vries said. "But from Putin's perspective, it looks different."
But other experts believe nationalism and power is behind Russia's moves.
"War comes from a mixture of motives," said Charles Maier, history professor at Harvard University. "That was true of World War II and whatever conflicts exist today. Putin would like to believe he can reconstruct the influence the Soviet Union had during the Cold War. Ukraine was part of Russia for a long time; he's trying to show it won't be easily absorbed by the West. This is as much as power politics as economics."