Trump's dark warning on U.S. elections: 4 takeaways

President Trump cast American elections as under siege Thursday night, describing a system riddled with vulnerabilities that hostile foreign actors and unauthorized immigrants are exploiting. Driving the news: Trump's dark, foreboding 25-minute address from the East Room of the White House served two main purposes: Build support for his SAVE America Act, which would require proof-of-citizenship for voter registration and is stalled in the Senate. And return to a topic that fixates him perhaps…