7 Safe D seats in Washington is actually really easy. I don't see how the Democrats don't work out a map like this if they still hold 7 seats after the election, especially if it focuses on incumbent protection.
https://davesredistricting.org/join/452fd660-151a-4723-89bc-b159225412eb
WA-1: Clinton +10.4%
WA-2: Clinton +24.5%
WA-3: Trump +7.2%
WA-4: Trump +22.1%
WA-5: Trump +13.6%
WA-6: Clinton +10.8%
WA-7: Clinton +77%
WA-8: Clinton +31.5%
WA-9: Clinton +20.5%
WA-10: Clinton +10.4%
I didn't even really do anything special or make any awkward arrangements with this. The only reason for WA-2 to pickup Chelan County is to make the Yakima split easier.
6 and 10 are not safe D. They would flip in an R wave year
