This is an in-class assignment, ideal for a 45-minute class period, designed specifically for high school. The worksheet helps students to review Manifest Destiny (which they should have already encountered as middle schoolers); for those who have completely forgotten the concept or never learned it, the worksheet additionally serves as a good introduction. Students work through a series of tasks with a partner (brainstorming, viewing material online, answering discussion questions, and, finally, analyzing two pieces of art), discussing as they go along. You will need access to the internet and at least one computer (or device) per pair of students for this in-class assignment to work.
Using the information after the students have completed the tasks is also an important part of the assignment. I have each set of partners use a Google Doc when they write down their answers, to make sure that they can each have their own copy saved after they've handed in a copy to me. It makes a good study resource for them to refer to for upcoming quizzes or tests. Additionally, I use a few minutes of the following class period to go over the assignment in class to make sure that everyone really understands the concept of Manifest Destiny (usually we just do a quick class discussion and I encourage students to add to their answers in their notes if needed).
For grading, I prefer to just assign a completion grade on work like this instead of using a rubric, because part of it (the art analysis and brainstorming) are open-ended. This encourages students to bring in their own ideas instead of always being chained to the focus on "having THE right answer."