Great question. Scout doesn't currently search for synonyms and related words to what you're typing, so for the most part, it's as smart as the search query is. And some phrases we commonly use to discuss an issue tend not to appear in legislation.

For example, "same sex marriage" returns many results, but gay marriage" returns not a single bill.

same sex marriage - https://scout.sunlightfoundation.com/search/federal_bills/same%20sex%20marriage
gay marriage - https://scout.sunlightfoundation.com/search/federal_bills/gay%20marriage

We would love to work on ways to improve this and make the tool smarter, but it's also the case that this is a power user tool, and precision and predictability are also virtues that power users want out of search engines.

What we suggest is to create searches for all of the related terms and synonyms around the issue you're interested in. Where we'd like to go in the future is to make use of the related terms that expert users enter, and offer suggestions and other smart help to users who aren't as familiar with those synonyms and terms of art.

As an aside - we do have a particular kind of "smart search" around citations of the law (the US Code),