"We can’t abdicate our position in the world for the next three years. So Republicans will have to resist the temptation to weaken him when the cost is weakening the country. A party that for at least two generations has held high the banner of American leadership and strength should not cast a vote that obviously risks a damaging erosion of this country’s stature and credibility abroad."
From Bill Kristol's explanation of why "yes" is the correct answer for Republicans.