Here are my concerns about a Bernie candidacy ...

[KingCharlemagne]

31. Start with this fact of American electoral politics: each major party's candidate starts the

General Election campaign with a 'base' of about 40%. That leaves 20% of so-called undecided (or 'swing') voters to be contested and those 20% may ultimately decide the outcome (keeping in mind the importance of certain battleground states). IOW, Sanders would not need to campaign in California or New York State with their massive electoral college vote blocs, since he presumably already has a lock on both states. Likewise, the Republican nominee need not campaign in Texas or Kansas, for exactly the same reasons.

So, in essence, you're constructing something of a 'red herring' with your concern about a 'national campaign.' Sanders and his Republican counterpart will slug and slog it out in a few key battleground states, like Ohio and Florida, and the winner in those will occupy the White House, come January 2017.