Debating each other's arguments is interesting, but doesn't get us any closer to real solutions. I'm an engineer, not a lawyer. The "what" is that regardless of an Ike Dike, and even with a barrier across San Luis Pass, every study says Galveston is vulnerable to bay-side surge flooding. That only gets worse as sea levels rise.
The challenge is the "how." I think something we can all agree on is building a levee on the north side of Galveston is an inelegant proposition. The fact that it's messy, and not necessarily popular doesn't preclude it from being done; I'm sure a lot of folks thought that about building a seawall and doing a grade raising.
There might also be some other interesting solutions for addressing bay-side surge; what about reinforcing/expanding the existing Texas City Dike, extending it to Pelican Island, gating the mouth of the harbor and connecting it to the east end of the island?
There may be other potential solutions that don't involve a messy ring levee. Even if that's the best/only solution, we're all in this boat together, so lets work collaboratively on finding the best solutions for all Galvestonians.