Comment by watersb

In Larry Niven's "Known Space" universe of science fiction stories, ground-based lasers built for interstellar propulsion end up being used to fend off alien invasion.

Example story "Madness Has Its Place"

https://temp.larryniven.net/?q=bibliographic-reference/madne...

Available at Baen's Library https://www.baen.com/Chapters/0671878794/0671878794___3.htm

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(okay, not necessarily Earth based lasers; perhaps the "ground" is more like "asteroid" or "tiny rock space station"...)