I'm struck more by the words themselves than the historical context of them. This sounds like something we might have heard in the last Presidential election. It's a slogan, and its aim is to unite people to work toward a common cause. Think of it as a rallying cry, designed to motivate people to work together.
Now, where would such a thing be needed? I suppose wherever the task is big enough and important enough to require a group effort. That's why I thought of politics, but here are a few other issues which might require this kind of collective thinking: the environment, human rights, social injustice, conquering a disease, making a dramatic breakthrough, producing something of lasting value.
It's interesting to note the open-endedness of the phrase: together we can___________. Also the implication that without each other, this task, whatever it is, can't be accomplished.
Just a few random thoughts for you.
These words of the politico are similar to that of the labor unions: "In union there is strength." So, if one searches for facts that support the strength of unity, then there is much information to be gleaned in the history of the AFL/CIO, for example.
Certainly, during times of war, especially in World War II, when the country rallied and united against the threat of Nazism and the Japanese, there was, indeed, the thinking relative to "together we can." And, with the resources that America had, this thinking was realized.
On the negative side of the thought behind "together we can," history shows how corrupt officials have enacted legislation in their favor, etc. For, there is strength in numbers, whether the objective is honest or not.
These thoughts are all really good. However, I was thinking more like "together we can" starting from anyone's community going on to country. Like starting a community garden together, raising awareness together....etc. Also if you have any thoughts on what can we accomplish together. Also be aware that these thoughts, that i will write into an essay, will have to be from a seventh- eighth grade kid's point of you. So just things KIDS can do in their community.