Same-sex marriage in the United States 

I've undone your revert on the intro to this article, because although it's in good faith, I think it's mistaken. The reason you gave was that the information is elsewhere in the article, which is already long, so the intro shouldn't cover it even in summary, as it's in the main body under "History". Although I respect your intent of keeping it concise and avoiding redundancy, the Manual of Style for the intro is quite clear:
 The lead serves as an introduction to the article and a summary of its most important aspects ... [It] should be able to stand alone as a concise overview. It should define the topic, establish context, explain why the topic is notable, and summarize the most important points, including any prominent controversies ... The lead is the first part of the article most people read, and many only read the lead.

The issue here is that the intro currently says that state bans were declared unlawful in 2015, 38+ states provided some rights as from 2003, and Windsor gave federal rights in 2013. There needs to be some mention of the backdrop and prior controversies as they were huge, and an increase from 2 to 3 paras to add substance on the background + context is (in my view) appropriate: even very long articles still need a proper introduction that summarizes their contents. Take a look at African-American Civil Rights Movement (1954–68) for an example of the intro to a long-ish article. 

If you disagree with my reasons, maybe we can take it to the talk page and raise it there/see what others say first, before re-reverting. FT2 (Talk | email)