For the longest time, I've been wondering just how effective would Star Trek universe weaponry be against the type of energy shields employed by the ID4 aliens. I've had some musings about the ID4 aliens (aka. Harvesters) in vs. scenarios with the Star Trek universe, but they usually don't really involve the main supporting cast from any of the 2 Independence Day films, and feature solely the Harvesters themselves, along with their ships and whatever technology they possess, and just dump them into the Star Trek universe proper.
Since I've been playing a bit too much of Star Trek Online, it already has me guess-timating that the principal offensive weaponry employed by the Harvesters would be Plasma-based weaponry, not unlike the Borg and the Romulan Republic. I would think that Plasma weaponry is rather effective vs the selection of technologies of basically every political faction that exists in the Star Trek universe.
In my head fanon, I would imagine a world similar to 20th Century advancement getting targeted by said Harvesters, approaching from the relative position of the Galactic Center...placing this hypothetical 20th Century analog in the direction of the Sagittarius constellation (if seen from Earth). Since this is a pre-warp civilization, it will be difficult to bring in a warp-level civilization into the fray, and the only way I can think of doing is is to involve Nimbosian Pirates abducting a rather important political figure and using said planet as a hideout. Said political figure is exposed to the natives of this planet and interrogated. It isn't long before the invasion happens when the Harvesters make planetfall. One such person (of this Sagittarian planet) who doubts the connection between the imprisoned political figure and the Harvesters converses with said figure, and convinces him that the Harvesters are more than capable of encroaching into Federation and Romulan space. Being unable to extract the prisoner, the native was instructed on how to operate one of the Nimbosian shuttles and leaves the planet to warn any of the 2 political bodies in the Beta Quadrant.
I would like to think that the Harvester Invasion happens well after the Hobus Supernova, sometime after the formation of the Romulan Republic. An Alliance patrol intercepts the commandeered Nimbosian craft and takes the Sagittarian alien into custody. The Alliance convenes to determine whether to extract the important political figure from this Sagittarian world vs. upholding the Prime Directive. Seeing that the Harvesters will not stop at this one world and will move onward into Romulan and Federation space, the Alliance dispatches a joint fleet northward towards the Sagittarius area to fight off the Harvesters and extract said political figure (perhaps a Klingon ambassador?).
Thinking about it, I would actually love to see an engagement between an Alliance Joint Fleet (Federation, Klingon, Romulan, Cardassian, Dominion, etc) vs the Harvester Mothership in orbit over said Sagittarius world.