I try to have everything I do informed by my understanding of the Christian faith. And that includes evaluating political candidates, both on their own morality and on whether their policies address the issues of caring for neighbor, justice, etc. that are foundational to my faith.
I speculate that for evangelicals, abortion is the top priority issue and thus electing a President who will nominate anti-abortion judges to the Supreme Court. Fine. But I would also expect them to weigh in on other faith-related issues -- to lobby the Administration to end separating immigrant parents from their children, to lobby for better health care and education for the children after they are born, to oppose dog whistle approval messages to white supremacists, to challenge EPA measures that run counter to God's call for good stewardship of the earth, etc., etc. I expect of myself that I would lobby the President I chose if he/she promoted policies that I believe run counter to my faith.
As for current immigration policy, that was not an Obama policy. Unaccompanied kids were held. But now even parents coming legally -- following proper procedures to seek asylum -- have been separated from their kids. Whatever the parents status, kids should not be held hostage by this policy. As I wrote, I expect people of faith, including those who share my theological understanding, to be vocal about faith-relevant issues no matter whom we voted for President.