POTUS in Singapore: When did Trump's predecessors last make high-profile visits?

We'd like to entertain the notion that, with the historic 2018 Trump-Kim summit, Singapore's going to cement its place as a nexus for matters of intercontinental importance. Perhaps one barometer of that is how frequent the most powerful man in the world - the President of the United States - visits. Yet that track record is not as illustrious as one may imagine. Here's a roundup of the brief history the island-nation has had with POTUS.