The question from evangelicals to Jews, and even to mainstream denomination Christians, has a plaintive quality. It is the anger of hurt, not hostility.
They are not siding with us for good reasons and bad. First, the question can fairly be reversed. If evangelicals really want other religious people on their side in the cultural battles, upholding (for example) the institution of marriage and the nurture of the young, they should consciously seek that alliance. Evangelicals know how to rouse each other for specific tasks, but don’t stop to remember that even those who tend to agree with them do not respond to the same language and appeals. Parachurch ministries, in some ways the connecting fibers of evangelicalism, are particularly bad at this. They focus their energy on convincing the like-minded that their particular cause rises to the level of requiring action. A host of other groups who might occasionally or more passively support a cause are left unmentioned. Mormons have joined cultural alliances because they respond to much the same language and values, not because evangelicals have done much good work recruiting them. Christians from mainstream Protestantism have a slightly different focus, framing needs differently. Roman Catholic activism uses language and concepts that are a little further away; Eastern Orthodox further still. These are language and conceptual differences that are easily overcome with a little listening. They draw from the same scripture; they are filtered through the assumptions of the American experience. Evangelicals recognise the sources immediately – it’s just not the way we would have put it, or the focus we would have had.
This is even more true in speaking with Jews. The gap is wider, but not uncrossable. Evangelicals should not always leave it to others to make the adjustment, having to parse language closely to see if there are any theological time bombs included in the proposals.
For example, all groups might heartily support the idea of strengthening marriage, yet have different focus. Some want to do battle against cultural forces which undermine marriage; others might be drawn to marriage enrichment, reducing domestic violence; strengthening the surrounding community; or any of a half-dozen other worthy causes. If you want them to support your causes, consider supporting theirs. I suspect that evangelicals have little idea what causes the synagogues support in their community.
Secondly, if you are asking who religious Jews will side with as their second choice, secular Jews or religious Christians, remember that they have good recent historical reasons for suspecting that Christians might not reciprocate the sentiment, and in a pinch, choose secular Christians as their second choice over religious Jews. Protestations that this was across the water and that our history has been different will only go so far.
But the third reason is a bad one, and evangelicals should have no illusions about it. I don’t think that urban, well-educated liberal Jews are dramatically different in their cultural attitudes than other urban, well-educated liberals. If they are underrepresented in the military, they are not conspicuously different than the gentiles of their neighborhoods. If they regard people from the South and Midwest as general yahoos who like the wrong music, wrong clothes, and read the wrong authors, they do not do so in a way significantly different than other urbanites. If they are entirely beholden to the Enlightenment framework of history, the self-congratulatory picture of how benighted the earlier people were compared to their wise selves, it is because they are a product of the same schools and authors as the gentiles in their districts. Do not assign Jewishness to what is primarily a cultural prejudice. On the other hand, don’t expect that Jewish historical religiosity will overcome it either. The Arts & Humanities Tribe has contempt for the flyover American culture, which is the primary competitor to their own cultural dominance. The lash out for in resentment for status reasons, though they couch it in other terms. Liberalism is its own religion, and a very intolerant one. (If Elisheva is still on board, she looks to be an excellent example of an exception to this stereotyping of us. Be alert for such.) (Update: Okay, maybe not.)
The fourth reason would perhaps be a bad one, but as so few people are aware of it, I’m not sure it can count for or against anyone. The Anglospheric, especially American experience of Jews is profoundly different than in other countries. The religious plurality which allowed all of us, including Jews, to flourish here is deeply related to the evangelical belief that conversion must be a result of persuasion and individual decision, not government decree or cultural pressure. It is not only evangelicals who believe in persuasion in religion, of course, but we are particularly known for it. And particularly despised for it. The irritation, even deep insult, that people feel when we attempt to persuade, is not perceived as connected to the stunning newness of the American experience. Such reliance on persuasion rather than fiat is so natural to Americans now that they believe it is the natural state of affairs. They consider it some vast inconvenience and intrusion when others try to convince them. They no longer remember the alternatives were far worse.