Instead of posting the answer as I see it, I'll say more about how I came to a view, and you can see how you view it.
Think about the standard of living - the wealth - of the US, compared to the majority of mankind who lives in terrible poverty. China, India, Mexico, and so on.
Now ask why we are so much wealthier. There will be a long list of important reasons, but it'll help you to lay out the groundwork for the effect of globalization.
A history of being free from invasion with the protection of oceans? The benefits of a slave class for the first couple hundred years? A wealth of natural resources? A strong educational system? Economic imperialism which led to many other nations shipping their raw resources to us for us to use in our products? A stable political system? A strong economic system? Controlling much of the financial markets? Keep going, and see what your list has.
Then take a note of the current world status. How is the US doing at preserving its advantaged that give it much higher wealth? Is its military might still used as broadly and ruthlessly for control, for putting in puppet dictators to serve ou needs? Not really. Our advantage in advanced skills? Other nations are now graduating far more Ph.D's, more scientists, than we are. Our financial strength? Squandered on our debt from Reagan on. Our advantage in manufacturing infrastructure? You know the answer there.
Ask what would happen if you could snap your fingers and broadly implement globalization, how it tends to work now. Competition decreases income. This is why workers would work for barely enough to eat before labor reforms; if you did not accept the low wage, you starved, and the key to higher wages was the right to collevtive bargaining, decreasing the competition between workers. By the same token, from the other side, capitalist businesses make the most when they have monopolies, while in commoditized markets - look at food or generic PC components today, for example - profit margins can be around 2%. What globalization does is to increase the competition for labor, but not only that, it increases the competition with people who can work for far lower wages, because they don't have our nation's standard of living, our currency. This has the effect of plummeting wages for the US workers, at best, and displacing them much of the time.
But doesn't that also hurt the US owners? Well, not exactly. Yes, for some who aren't too flexible, but for those to whom a dollar of ownership is a dollar of ownership, they can simply be the ones profiting from those suddenly lower labor costs, at least in the short term while our nation still has its wealth, ready to blow on cheap goods - which lasts until we've blown that wealth, and are suddenly faced with being a lot more like China, as far as the workers, while the owners have put all that wealth into their pockets.
It's bad for society to suddenly end up having spend its wealth, lost its infrastructure, harmed its currency, its credit worthiness, skyrocketed its debt, and so on.
One analogy I use is that you are doing ok, in your house, and a poor family moves in next door who you have much more than. At first, that can work for you, as you pay them to mow your yard, to clean your home, with a small expenditure. But what happens when you are paying them so much to give you so many services - massages, personal chef, dance shows to entertain you - that your wealth is being transferred to them? Where will that get you? Broke, and them with a lot better standard of living than you.
That's sort of what the US is doing with globalization - it's recklessly doing it, instead of doing it in any sensible manner.
It'd be great to have a sense of the injustice that the poor family above faces, and to want them to prosper, with access to education and so on - a win-win as they are closer to your situation economically, as they produce more. That's analogous to the US not sending its wealth to China as they develop and increase their productivity. But being reckless will hurt you, and that's what we're doing. Every expert I hear says China has us over a barrel they own so much of our debt - and that's just one nation, and the trends are terrible.
Not only are there risks of when the other nations stop loaning us money and buying our debt, but how can anything else happen than a disaster if the situation isn't changed? When the crash starts, whoever gets out early will do better than those who wait, creating a stampede - and how long can responsible governments keep putting money in to prop up the US economy, when they lose so much to do so? Only for so long, and then they'll start to get out, and I suspect it'll avalanche when it starts.
How does globalization work for American workers? That's an interesting question. They do get some benefit from the cheaper goods. It seems to me that there is a 'right way' to do it.
The bottom line is trying to help the poor nations rise to our wealth, rather than lower our nation to theirs. To the very wealthy, that's not such a priority - they function in terms of the percent of the society's assets they own, and it doesn't matter that much whether they increase their share with the rest of society doing better or worse; impoverishing the average American is the best way, perhaps, for them to be able to buy up assets. But it matters a lot to the American workers which way it's done.
This is why it's such a concern to see the bottom 80% get none of the increase in weath of our nation after inflation the last 25 years, while the top has skyrocketed.
I think if you look at when a society advances the most for its public economically, you will find that it's not in the periods in which the most wealthy secured their position and increased the concentration of wealth at the top, but rather when those assets were more equally distributed and available to fuel the economic system with incentives for a lot of people. Look around the world, do the nations with the most corrupt roluers and oligarchies grow a lot, or do the societies with less concentration of wealth?
Admittedly, one segment of society benefits when it can exploit another - as we did with slavery and immigrants. That's like your hiring the poor family next door to build you a new patio. But that's not the situation we're seeing now. The US is greatly harming its economic standing for the benefit of the few most wealthy, who are squandering our nation's well-being, in no small part to undo the progress in our own labor industry won through the first half of the 20th century, removing it by forcing competition overseas.
To return to my point on competition, when companies build facilities in three regions of the third world and then make the regions compete for which they'll use, it's good for the companies and bad for the workers (and environment etc.) That's why I think we need more and more collective activities globally now between labor as the only way to prevent a huge shift against workers.
Indeed, I think the case can be considered that the trends caused by globalization may determine whether the human race returns to its norm in most of its history of being a mostly feudalistic economy, or whether the tiny bit of the history of the human race where strong middle classes developed in the 20th century can be protected.
Does protectionism have a role in protecting our own workers' interests to have a more gradual, better-planned globalization to let other nations develop? I'd say yes.
Unfortunately, the issue now seems to be between the blind and self-interested 'free trader' approach, and a simplistic 'anti-free trade' backlash.
What does your looking at the effects of globalization tell you?