Can the Democrats create a firewall?

[West_Midlander]

I don't think there is and I don't think there can be a firewall. I think depending on the candidate and how things shape up through the primary, convention, general election campaign and debates, it could be a Trump win similar to Bush 2004 with him taking the popular vote (as well as the EC), it could be a close one, or it could be a large Democratic win by a similar margin and electoral result to Clinton 96 (not the same states of course and no prominent third-party campaign, though).