President Trump kept America out of new wars and brought thousands of brave troops home from Afghanistan, Iraq, Somalia, and many other countries. Joe Biden has undermined our military readiness and surrendered our strength to the Taliban.
When Trump pulls troops out of Afghanistan, it's "bringing thousands of brave troops home," but when Biden does the same, it's, "surrendering our strength to the Taliban." He brags about "keeping America out of foreign wars" while at the same time bragging about assassinating "the world's number one terrorist," Iranian general Qasem Soleimani, which was an extreme act of provocation.
This is taken from the issues page of Trump's campaign website, and there are several more statements relating to foreign policy, frequently and boldly contradicting each other. It's a perfect example of the "If By Whiskey" tactic. So what's actually going on here? Well, to understand the reasons for this equivocation, we need to analyze the foreign policy positions of Americans.
Broadly speaking, people fall into one of four camps: Idealist Hawk (liberals), Idealist Dove (libertarians), Realist Hawk (nationalists), and Realist Dove (socialists).
Idealist Hawks believe that US foreign policy is driven by benevolence and spreading freedom, and the fact that it repeatedly fails to do so (Iraq, Afghanistan, Vietnam, etc) is explainable by a variety of excuses. Generally, they are more interested in current events and easily persuaded to support intervention based on seeing a bad thing happening, without a broader analysis or explanation of the situation or how things have played out historically.
Idealist Doves also believe that US foreign policy is driven by benevolence, but they see that as a bad thing. They are generally right libertarians or hold libertarian values, they see war as another example of wasteful government spending as it tries and fails to improve people's lives, which they generally don't see as a valid goal in the first place. Being idealists, they are still rather easily duped into supporting war and militarism, often, they will support a "night watchman state," with police and the military being the only legitimate functions.
Realist Hawks are nationalists who believe that states pursue their own material interests and are right to do so. They are incapable of distinguishing between the state's interest and their own. Some few are rich enough to actually receive benefits from US foreign policy, but most just root for America in the same way that they might root for a football team.
Realist Doves, which I am a part of, do not believe that US foreign policy is not grounded in benevolence and does not benefit the people it claims to be helping, but also (generally) that it doesn't benefit the majority of people at home. We see it as being driven by and for class interests, and are opposed to the class it benefits.
Trump's foreign policy equivocation, and his "America First" slogan allows him to appeal to both the Idealist Doves (libertarians) and the Realist Hawks (nationalists). He can't consistently take any line on any specific thing. If by Afghanistan, you mean a disastrous nation-building exercise, wasteful government spending, and endangering our troops for the sake of helping foreigners, then of course Trump opposes it. But if by Afghanistan, you mean exerting American strength, intimidating Russia and China, and weakening terrorists to keep America safe, then of course Trump supports it.
In reality, to the extent that Trump has coherent beliefs at all, he is a Realist Hawk, a nationalist, and his record reflects that. But part of the reason he was able to get anywhere was because he was able to triangulate and equivocate well enough to dupe anti-war libertarians.
Unfortunately, in American politics, the conflict is generally between Idealist Hawks and everyone else. This is part of what allows the nationalists and libertarians to put aside their differences (the other part being that libertarians are easily duped). Realist Doves are not represented anywhere, the Idealist Interventionists consider us Russian bots along with everyone else who disagrees with them on foreign policy (regardless of how or why), the Idealist Doves are extremely unreliable, and the Realist Hawks may see the world in a similar way but have diametrically opposed priorities.
tl;dr: Trump's halfhearted antiwar posturing is an obvious ruse that only an idiot would fall for, but painting everyone skeptical of US foreign policy with the same brush helps him to sell it and to paint over ideological rifts that could otherwise be potentially exploited.
Touche, you got it on the point...