Christianity cannot be used - and the attempt should not be made - as a means to the end of good secular government.
(For instance, Christianity should not be used as a means of making people behave well.)
The word 'good' in good government, indeed, has a quite different meaning from a Christian and a secular perspective: in that salvation is the aim of Christian government while happiness/ minimization of suffering is the aim of secular government.
Atheism is inadequate as a basis for good government - such that all secular government is unstable and self-destroying except in the short term.
(i.e. atheist government can last only a few generations, and then only by virtue of inertia from a previous stable polity.)
Furthermore, most (almost all) Christianity nowadays is thoroughly corrupted by worldly secular thinking - in the West this means that almost all the leadership of Christian churches are primarily politically correct (leftist, progressive) and only secondarily Christian, hence in practice work against Christianity, in one way or another.
So, there is need for discernment.
To find the small amount of real Christianity among a vast mass of corruption and error and lies.
And to prepare, if possible, for worse to come (prepare spiritually, I mean).
It is very likely that Christians (real Christians) are not going to be on the winning side in this world.
At least, things have been getting worse from a Christian perspective for such a long time, and are now very bad indeed; and much wiser heads than mine have perceived that this is unlikely to be reversed (except perhaps temporarily and in a localized way) - and indeed things are likely to get very much worse.
SO (what I think is that) Christianity is probably 'not a good bet', not an expedient choice, if someone is looking for power, status, influence, worldly happiness or indeed freedom from suffering.
But only a valid choice for people looking for reality (i.e. The Good: approximately for Truth, Beauty and Virtue): looking - that is - to save their souls and (perhaps) those of (some) others -
...but not a good bet for those looking to save a 'civilization', or a nation, or an ethnicity or any large grouping. Since all such are now so thoroughly corrupted by worldliness that they do not want to save their souls (not, indeed, believing that they have any souls to be saved).