[Suicide Junkie]

Will the ships blow away the planet if the troop landing is a stalemate?

If not, use 2-3 Large Transports full of heavily shielded troops.

I was a race with 50% ground combat, and I took an 8Billion pop planet that way. First load had 375 troopers, second boat was a smaller transport, with only 125 or so. My troops got whittled down over 5 turns, and at the end, my troops lost by the slimmest margin (<10% of the militia survived)

The key is that militia don't regenerate unless there are no foreign troops waging war on the surface.

So, if one boatload of troopers can survive 10 rounds of ground combat, dump 1000 of 'em on the planet and wait.

If you break up your fleet into squads, with each troop transport as leader, you can probably get all the transports to drop and run, while under cover of the warships (use a formation with the leader in the middle)