Mormon 4:18

And from this time forth did the Nephites gain no power over the Lamanites, but began to be swept off by them even as a dew before the sun.

From this time on, the Nephites had no power over the Lamanites. They began to be wiped out like dew in the sun.

From that point on, the Nephites never gained ground again. They were swept away like dew before the sun.