Delaware and Oregon don't have a recent history of being swing states, whereas Ohio and Iowa do. I would argue that it's possible that Delaware and/or Oregon vote Republican in 2020, but very, very unlikely.
I could see Kasich potentially doing quite well in Oregon, but not winning the State, against a Democratic candidate.
Reason being, is in or for a Republican to win statewide, they not only need to max out their votes in rural areas (Check Trump '16), perform exceptionally well in Mill towns (Still potential gains there vs '16 I supposed hypothetically), but most importantly be competitive in the Portland suburbs of Washington County, upper income areas of West Portland, Inner Portland wealthier suburbs like Lake Oswego, etc. and win by quite solid margins in Upper Middle-Class precincts in Salem, Eugene, Corvalis...
The only way I see that scenario happening is someone like Kasich, would be able to harness the traditional latent "Moderate Republican gene" that exists in much of Oregon, but it's still a major strain on my brain trying to figure out even in that scenario how a Republican could modify the margins enough in just the right places to take the ball over the finish line.
I'll let others speak to Delaware, since I haven't been there in 15 years, but yes your point about Iowa and Ohio having a immediately recent history of swing states was the correct answer....
