Just going through the tool kit to see which hammer to use...
We've got numerous defensive systems that could be pressed into use as "weapons". Then again, a rock can be used as a weapon if you hook a guidance system to it and accerate it to a significant percentage of the Speed of Light.
On top of that, we also have quite a few research projects that could be pressed into service. From Coherent anti-matter, gravitonic wave sheer generator, transporter "tele-frag", and yes..... I'm still working on a wave cancelling laser sword somewhat similar to a Jedi Lightsaber. The major difference being that one of the opposing phase "blades" is a stream of anti-matter "positrons". An emitter produces two streams of "virtual" particles. Somewhat similar to the virtual photons that pop in and out of existance all the time. However, as they amplified into a coherent stream, one of the streams is also phase shifted to be 180o from the other blade. Instead of annihilating at the intersection point, their energy potentials cancel out.
Still getting some rather spectacular flashes of energy when you just whip one of these things through the air itself. Cutting anything is actually dangerous. There really isn't much of a way to make it both look cool, and be non-lethal to the user. There is just too much radiation output from the anti-matter collision events. A similar principle is what is going to drive our "mining" drills.
No... appeasing Aliens to get them to not "hurt us" would only be an issue if we run into the Q.
I'm not particularly impressed with "Empire" technology. Obviously, what they have done is find a few items of tech that are essentially bulletproof, and they have modeled their society around them, much as the Roman Empire was built on the soldier's short sword.
The Lightsaber is a useful tool, similar in rugged dependability to an electro-magnet. It is the energy density that is the key to it. If you think a "phaser on overload" makes an explosion, you haven't seen anything until a lightsaber can be made to cook off.
It's darn hard to do, though. They aren't designed to operate that way.
Essentially, the lightsaber is a portable, extendable event horizon. Thus, in operation, it is not depleted of energy, but gains energy with even its passage through the air. By extending the optical path of the event horizon, one can make a blunt knife which cuts through anything. It is the equivalent of a high-speed, high-current, plasma torch with acid etching.
This explains why two lightsabers don't mingle. Each event horizon is tying to dominate its own area of influence. They become like similar pole magnets repelling each other.
Shielding against a lightsaber is difficult. It requires force field enhanced materials which are not disassembled by an event horizon. As I said, difficult.
But the tool itself is quite simple and useful, as has been shown. It is totally ineffective at long range, however, and would be inappropriate for starship defense.
If our boys in Iraq had to go up against Jedi Warriors, I would recommend the use of triple barreled single shot rifles. The pattern of three bullets arriving simultaneously, with a slight spread between them, would be a challenge for even the most adept Jedi to counter.