Big Tent in political strategy means joining together towards a common goal. I, Person A, may not share all of the beliefs of Person B. But Person B agrees with me on a vital issue that is of particular (and usually an immediate and urgent) concern for our area. So we join together in a Big Tent Coalition, trying to sway as many people as possible towards our position so that Person C , our common enemy, doesn’t gain any ground. These coalitions usually are short-lived but it’s fine if everyone involved understands the nature of the coalition