The underlying problem (Shortest Vector Problem) is known to be NP-Hard.
We know, via mathematical proof, that if there is a solution to SVP that's solvable in polynomial time then it would necessarily mean that it is possible to solve any NP problem in polynomial time.
This would be astonishing, to put it mildly. It would be as if physics suddenly discovered that things could move faster than light and have negative mass. Physics would get wormholes and computer science would get "Arthur C. Clark magic"* programs.
(*“Any sufficiently advanced technology is indistinguishable from magic.” )