President-elect Donald J. Trump refused on Tuesday to rule out the use of military or economic coercion to force Panama to give up control of the canal that America built more than a century ago and to push Denmark to sell Greenland to the United States.

President-elect Trump is encountering some unlikely openness from Democrats — and hesitance and confusion from Republicans — with his talk of acquiring Greenland and the Panama Canal. Why it matters: Any such effort,