War with Russia is unlikely. Even though the Cold War is over, the MAD doctrine is still in effect. Nuclear weapons are very good at preventing conflicts from escalating into all out wars. Despite disarmament efforts, the US and Russia still have large nuclear stockpiles.
This actually cancels out a number of potential WWIII scenarios between modern global rivals. All of whom are current nuclear powers, or are nuclear capable.
India vs Pakistan
Israel vs Iran
China vs USA
Russia vs NATO
North Korea vs USA
I won't say that we'll never see a global total war again, but the current political climate just doesn't favour it. Any wars in the foreseeable future are going to be highly regional.
Islamic State poses an interesting problem. It's a major regional threat, but not a global one. Their very ideology is anti-science, so they lack the ability to produce advanced weapons. Plus they haven't won any powerful allies. While the Saudis and Iranians may agree with them on certain ideological issues, they will not sacrifice their own sovereignty or interests. Both want to maintain a regional hegemony. Neither Russia or China are going to supply them for fear that they'll ally with their own militant Muslim minorities. IS has also put themselves at odds with other major Islamist groups like Al Qaeda and the Taliban.
If there were a full blown war with IS, it would be over fairly quickly. Any modern military would steamroll them in open combat. The only reason this hasn't happened yet is because no nation wants to be involved in the inevitable quagmire that would follow. The war itself would likely last a few months, but pockets of guerrilla fighting would continue for years afterwards. Same as we've saw in Iraq and Afghanistan. So right now, the focus is containment.
What ultimately allowed IS to take root was the fall of Saddam Hussein's Iraq. So much for the Iraq War stopping terror. The US doesn't like to admit that fact. Turns out destabilizing regimes, even bad ones, is not the best path to global peace. A lot of nations are going view the current conflict as the Americans' mess to clean up.
TLDR: Jim Rickards is full of shit. Just trying to justify the obscene amount of taxpayers' money the CIA and other intelligence agencies piss down the drain. Snowden sure kicked up a hornets nest.
I don't think MAD will ultimately prevent total global conflict, though it works as a strong deterrent. However, I think the premise will support the notion that nuclear weapons will not be used by state actors, because THAT is what opens up the can of worms. War can still happen, so long as parties don't go lobbying nukes at each other. Which is to say, people can and will still bomb the hell out of each other and send the tanks and troops across borders, and will do so with the typical risk/reward weighing that occurred prior to the nuke. What they won't do is willingly become the second nation ever to willingly drop a nuke on the lap of their enemy, because this time, that won't go unanswered. I think only the most literally psychotic understands that thread. Accepting that, standard warfare is still on the table, and will occur.
But today, with global economies so strongly interconnected, and with the lessons of the past actually firmly in mind, a world war is going to take one heck of a mess to shake up. I don't think this middle east nonsense will be the powderkeg. An assassination could still do it, but I don't think it'll devolve to that point so rapidly. Any movement toward all-out war will more likely follow the Japan v USA route, where heavy sanctions were imposed due to the various aggressions of Japan, starving them of oil; after so long, blood-thirsty Japan caved and decided to try to take out the entire US naval threat so that they could resume partaking in the spoils of Southeast Asia.
This theoretically could happen with Russia, but they don't have the economy to support it, and the sanctions haven't grown quite so harsh just yet. Harmful, but not damning. Even then, I don't see Russia snapping in the way Japan did, and had Japan been the only aggressor, I don't think that would have devolved into a world war, not with a war-weary Europe still collecting their breaths from that first go around. However, with Europe tearing each other's throats out, and Japan getting in the mix, that threw the whole world for a spin.
Russia wants the Northern Passage, and certainly want to lay claim to the massive hydrocarbon pockets in the Arctic Circle. As the world warms and the ice melts, that will further stress just about every nation. Couple that with wide-open untapped resources when things are becoming increasingly bleak, and a feral dog won't be backed into a corner; if things shape up a certain way, Russia could very well snap, but I don't see it happening.
I actually don't see much threat from China, not yet. Their entire economy depends upon, well, mostly "the West." You can't easily upset your largest customer and expect to be able to tango with them if you start slapping you around.
China, too, is likely to face their own internal strife. With such a vastly changing economy and a rapidly changing demographic balance (in terms of income classes), I think they'll have a mess of their own making to focus upon for awhile, sometime within the next 50 years. North Korea will likely get involved and ultimately implode.
The whole mess in the Middle East will ultimately just result in some redrawn borders. There is a remote potential that the M.E. will play out in a similar fashion as Europe, and global allies get drawn in and eventually borders get redrawn, but I think they just need their period religious fervor to grow, fall, and clean themselves up. The only variable is how caught up the rest of the world gets in their squabbles, which is a bomb of a variable if there ever was one, but it might not turn out as bad as some expect.