If Trump wins the election

It's an isolationist policy. The US military doesn't have military bases/presences across Europe (and elsewhere) out of the goodness of its heart or to protect Europe. They also do it because their military realises that its much, much better to have bases somewhere where they can strike an international enemy quickly from. It's a militarily mutually beneficial arrangement.

So, the US would lose that early strike capability. They'd also lose all the intelligence benefits having people on the ground brings with it. Also, should it happen and Europe was successfully invaded, US businesses would either temporarily or permanently lose access to one of their biggest trade export blocs and a large amount of access to imports too.

Even without the US, the EU combined forces are More than enough to deal with Putin; especially now that it's become startling clear that the emperor has had no clothes and his own strength was largely fiction.

That being said, they would have to be much more careful regarding China supporting Putin.

But also, as someone already mentioned, Trump is a bloviating idiot. The US isn't going to give up the convenience of having strategic military bases around the world; there's no way the pentagon and cia would never allow it. They'd outright Kennedy the idiot if it came to that.

It’s putin’s wet dream, to break the “Atlanticist” alliance and with it, NATO; to reverse the outcome of the Cold War. I think the ramifications would be too complex to game out with any confidence, other than stating the obvious: the world order would become multipolar (as putin prefers), with power centers in the USA, Europe, China, probably India, probably Russia. I could see US foreign policy shifting from its focus in Europe to the Pacific and intensified efforts to thwart China (which faces a demographic calamity that threatens any long-term potential for hegemony).

In reality, the ties that bind Europe to America (& Canada, Australia, etc.) are more resilient than the damage caused by your trumps, orbans, farages, etc. Rational actors will prevail when the stakes are so high.

They've already started to build up their arsenal in case of a Trump re-election.

I don't think them building a big arsenal to a point that they don't need the US would affect trade relations other than they won't buy as many weapons and ammo from the US.

What would have a big impact on trade and geo political relations is Trump being re-elected.

It'll certainly mean a huge loss if power and influence for the US. Right now the Europeans pretty much follow the US's lead when it comes to trade deals, political and military alliances etc. And they turn a blind eye to US imperialism in the Middle East and Latin America. All this would change and once the Europeans become more aware of their own power and willing to use it, they'll be a real geopolitical rival to the US.

I think Europe would then be forced to intensify its relations with China. Since China has so far been somewhat cautiously supportive of Russia's military expansion policy, or at least has not decisively sanctioned it, I think that would be a reasonable way of minimizing the risk of military aggression from Russia in the first place. I hardly believe that Russia would risk a military conflict with Europe if they could not expect support or even just tolerance of such actions from China. The consequence for the USA would then not only be a loss of strategic military influence in Europe, but probably also considerable losses in terms of trade and so on.

European nations will need to increase the sizes and capabilities of their militaries because the US is no longer a reliable partner, whether or not Trump gets elected again. As Trumpism has come to define the Republican Party, the US is no longer a reliable partner.

Because it is the process of years and decades, European nations need to start building capabilities now, even if Trump loses the election. The US has demonstrated that they can move to a Russian-aligned power as the outcome of a single election, which was unthinkable ten years ago.

I’m still having trouble wrapping my head around that, but every “adults in the room will prevent this” has proven very flimsy, and there’s no reason that a post-Trump Republican Party wouldn’t be subjected to the same kind of politics.

The only saving grace is that, as far as I can tell, there’s no post-Trump plan and the republicans might split into two parties once he’s no longer among the living. If that does happen, they’re going to have trouble winning national elections. Trump is such a narcissistic egomaniac that he will not have a successor designated, so it will turn into an open field.

The ramifications are that the USA would lose its position as world hegemonic power.

But that’s happening anyway. I’ve heard Ray Dalio’s argument about China being the next country up in a big cycle of hegemony, and it makes a lot of sense.

The basics are that in a period of upheaval, the US currency will devalue making the US’s ability to project power weaker, creating a reduction in the monopolarity of military power, and an eruption of military violence. It will begin as proxy wars and end up as fighting between the old and new hegemon. The new hegemon’s currency will take over as the most trusted currency of international trade.

There’s a lot more detail to the whole thing, but that’s somewhat of the gist.

The US took over the hegemon role from Britain, which won it from Spain, which took it from Denmark, if I’m remembering this right. Each of those transfers of world hegemony involved that same collection of connected events:

• old power has global military dominance
• their currency becomes international standard
• projected power is costly
• somehow hyperinflation happens
• reducing purchasing power and ability to maintain the global military presence
• they pull back to save resources
• new hegemon gathers influence in un-covered places
• fighting breaks out as result of more symmetric power distribution
• it morphs into old hegemon vs new
• new hegemon wins
• triggering change in dominant currency
• fueling their expansion from “new hegemon” to “the hegemon, duh”

We all grew up in the “The US, duh” era. When that was the answer to which country was top dog, which country would adjudicate in global questions, which country’s citizenship you want your kids to have to be safe and successful, etc.

By the end of our lives (I’m speaking from age 41, so y’all’s experience varies on this), by the end of my generation’s lives, we’ll probably be in the early part of the “China, duh” part.

But we’ll have a few decades where it’s the “Well actually, it’s China now” era. Where China’s on top, not only economically but morally and culturally, as a trusted world authority and the government the aliens meet with in the sci fi movies. But that it’s noticeably new.

Just like there was basically the “Britain, duh” phase, where anyone on earth would use “The King of England” any time they wanted to conversationally refer to the most powerful man in the world. It was just known.

This would unquestionably be a good thing for both parties. Only problem is that Europe is past the PONR for ever being a military superpower again, in my opinion. They simply don't have the young population to staff such a force and the population they do have would be so opposed to anything but the US-subsidized defense partnership they enjoy already, that I don't think it would happen

no longer in need of US military

Goodbye to Usamerican military means also goodbye to Usamerican ability of living on other nation's cost.

So, the USA has been trying to pull out of Europe for a while from a military standpoint. The EU is large and rich enough that it should be able to protect its own frontier without American involvement. It just happens to be that Europe would rather have the USA pay for its security rather than do it itself. So the EU is going to have to figure out creating a military and all that comes with it; effectively making the EU a nation.

If the USA leaves Europe, it will likely leave the Middle East as well. Oil isn't worth controlling any more and the USA doesn't have any interests there besides Israel. I expect more wars in the region as nations realign to more stable borders. This will likely include a lot of genocide.

I expect the USA to focus on the Americas, maintaining an anti-Chinese coalition, and trying to slow dedollarization. Asian allies will likely tolerate a fascist America more than Europe would.