The Right is good at making any issue into the issue of the day. There isn't one single reason for that, though the why/how isn't the point of this post. The point is that they make an issue a thing, and then there's a tendency by too many Democrats (electeds and pundits) to agree that the issue is actually an issue. Then they've already lost. For example, when Trump says we need to build a wall, and Chuck Schumer comes out bragging that some bipartisan bill is a much better way to achieve needed better border security because of all the wonky rea[zzzzzz...] all voters hear is "we need better border security" and what they conclude is "wow I guess we need that wall."
This is a bit of a caricature, of course, but the point is that once Democrats start telling voters that they're better at delivering what the Republicans say they want, they've lost. The Republicans have already made it their issue, the Democrats have agreed the Republicans are correct but we're just arguing about the details, and voters who think that issue is important know who to vote for.
And voters who disagree don't have any champions. It isn't true that if you give the voters a choice between a Republican and a Republican they'll vote for the Republican every time. Plenty just won't vote at all.
