[quote=AlienBastard]So, how about that ramming thing?

I heard that ramming the enemy spaceship tends to disintegrate everyone involved.[/quote]

Effectively impossible. Your opponent will see you from millions of kilometres away before you even make the attempt. They'll be capable of seeing and avoiding any move you make to try and match their trajectories. That isn't to say you couldn't ram an enemy, but the amount of effort involved would make it look like you're trying to wage a war by herding cats. 

[quote=catchamber]
What about a solar power laser array suspended by photon sails? A developed system could certainly build a host of them, and then focus their collective beams onto a single target from multiple angles. These arrays could also provide personal point-defense against kinetic weapons, and even be used to propel vessels equipped with their own photon sails.Brute-force conquest is an inefficient strategy for interstellar expansion, given the magnitude of energy being thrown around by both sides. Defenders have so many advantages against direct conflict with invading forces, it'd be much easier to just subvert polities into collapsing or rebelling. This can be mitigated by mental uploading, so every polity has copies of expert tacticians, but even that might not be enough.That's assuming total war is off the table, of course.
[/quote]

A Solar Laser Array is still effectively worthless. To get a powerful laser you're going to need tens of kilometres of sail your enemy could just sit twenty light minutes out and just throw shrapnel at it. And especially useless against kinetic weapons actually. If your enemy fires dumb slugs to intercept your big obvious targets your sensors would never see it before they shred your sails and weapon. 

BUT as I said to MDK before someone came and deleted several of his and my posts (Which if you ignore the slightly insulting nature of them, I broke it down massively.) interstellar war simply is not viable.

Let's say you can move a fleet of 10 ships at .2c This is a phenomenal feat.

Your enemy is 10 Lightyears away. It will take you 50 years to reach the enemy solar system at this velocity if we ignore acceleration and deceleration. Your enemy WILL see you forty years before you ever get near their system. Your acceleration will have been big and obvious...

Now lets say the enemy has 5 ships. But they can produce a further 2 ships per year (conservatively). They will have manufactured Eighty more warships when you finally reach their solar system. OF which the newest ships will be at least 50 years more advanced than your previous intelligence. 

Even if you, as an attacker, could build five ships a year and sent them as they were built you'd still never overcome the defenders advantage. 

IF you could accelerate something to .2c you wouldn't bother with ships, you'd just build large multi-ton dumb rods and fire them at .2c on a vector to intersect with the enemy planet.