“How can it broaden its appeal to up-for-grabs voters without alienating its conservative base? “
By sticking to the conservative principles laid out in the party platform?
The globalist-cheap labor party cannot win an election. A true constitutional-conservative party still could, but not for long with the path we're on.
This takes place long before the nominations and campaigns.
If you wait for the campaign and go out with the most perfectly nuanced appeals to people who usually don't vote for Republicans, you will usually lose!
Jefferson's DemocratRepublican party swept the Federalists from history by following that basic plan ~ first find the voters ~ then provide them the candidates they want.
NOTE: The Federalists imagined that the best people ~ men of education, position and property would select the best people for public office. We know how that worked. The only federalist most of us know of as a federalist was Justice Marshall, the 4th Chief Justice.
DISAPPEARED
SLATE WIPED CLEAN.
The only other federalist notion remaining is that of the GOP-e's belief that you pick the candidate first, then get the voters.
With 90 million adult Americans not voting at all seems to me a little effort could find that additional 6 million voters we need to skunk the Democrats!