Hold your fire!
I do hope nobody actually installs a laser up there, because that wouldn't be very smart. It wouldn't vaporize anything, but turn one big piece of junk into hundread smaller ones. And the small pieces would have total energy (and thus speed) of what the big piece had plus anything laser managed to pump into them! So instead of one big dent on the side, ISS would have a hundread small holes, making it look like a sieve.
That is the problem with space junk. More you shoot it, more you get. More energy you spend, faster it gets (and thus making it able to reach higher orbits and do more damage). Only way to get rid of it is actually go up there and somehow collect it, possibly dropping it into the atmosphere afterwards. Or at least stop making more, as everything in near orbits slows down over time and thus plummets to Earth eventually.
This will be done in near future. Almost immediately after something really important gets hit, because tradition calls us to wait for the obvious to happen, before doing something to prevent it.