Giving cluster weapons is a sign of weakness. If we could give enough artillery rounds, Ukraine wouldn't need cluster munitions to make up for the shortfall.
Ukraine is saying that they will start using them in the next few days. Not sure if they will make such a big difference anyway.
I believe "If we could give enough artillery rounds" was only half the reason. I do believe cluster bombs being efficient at clearing trenches, as I have read is the other half of it. Are there other efficient ways in which to clear trenches without further risking Ukrainian lives? There might be. I don't doubt the US has a cornucopia of weapon systems to choose from. For now I'm assuming cluster munitions clearing trenches is the right tool for the job.
I'm not convinced that this assumption is true. Ukraine had cluster munitions before, and they didn't seem to make much of a dent. Maybe it was the wrong time. This is why it's very interesting to see in the coming days or weeks if those weapons can make a difference. Ukraine right now seems to be stuck, and the front line hasn't moved in a week.
From my admittedly ignorant point of view, I don't see how cluster bombs can be
much more effective than anti-personnel rounds with proximity fuse. To clean a trench, you need almost a direct hit with regular artillery (because the trenches zigzag and have corners) and maybe cluster bombs will be able to increase the kill radius a little bit. Eventually Ukraine will have to still send people to mop up, and to me it seems that unexploded shells might be even slow them down.
But like I said, I'm no expert. We shall see.