I have to begin by stating that my knowledge of Mark Shea's alleged meltdown during this US presidential cycle really hasn't been at the forefront of my mind, the foremost reason for which being that Roman ecclesiology can get you into a difficult position. Shea, to his credit, follows Roman ecclesiology to its logical conclusions, even if it may or may not lead to the occasional bout of theological and doctrinal incoherence.
This out of the way, Mark Shea posits that the pro-life movement has been or will be compromised by supporting Donald Trump.
It needs to be said, Shea is sounding the alarm a little too late....about thirty years too late. The pro-life movement was thoroughly compromised when in the wake of Roe v. Wade, it aligned itself to politics that restricted the term to only one issue. In the pursuit of a political solution to a moral and spiritual problem, the pro-life movement was forced to rally behind politicians who had no genuine intention of overturning Roe v. Wade (which would be political suicide) and who proposed policy that would come into conflict with any honest reading of the Gospel and the Tradition. One cannot forget the pro-life movement's circling around George W. Bush, despite an illicit war and a foreign policy that blurred the protections of basic human rights over seas.
The inability to address a moral and spiritual issue on moral and spiritual grounds led the pro-life movement to cozy up to political interests and undercut any integrity the position had. This is why, in large part, the social justice movement (in religious circles) never adopted the pro-life movement's opposition to abortion - pro-life seems little interested in "whole life" and putting its money where its mouth is to support the integral development of lives (both mother and child) they thought they were saving.
But again, this did not begin with supporting Trump. Supporting Trump is the logical conclusion to both a) the trajectory the pro-life movement has been on, and b) the new alignment of the culture.
In the current climate, Christianity can no longer expect to yield public influence - those days are gone. The anti-Christian sentiment (led by marginal Christians no less) has grown to such a point that Christianity is now in a position of simply trying to be tolerated in the current cultural climate. Yes, it is more politics with the intention of supporting a presidency that will, at least at the level of federal law, allow Christian churches room to breathe, that is, adhere to certain convictions that are now thoroughly despised by the culture. Trump, by not making abortion, gay marriage, or religious freedom election issues, and by welcoming both evangelical Christianity and the LGBT community into his fold, provides an opportunity to find respite from the pressure Christianity has felt in the US for the past decade.
Is this the right approach? It falls in line with a 1700 year history of getting too close to the state to have proper distance.You can be the judge as to whether or not this is the right decision. There is no doubt that Christianity as a whole is in turmoil in the West - it is divided among itself and is looking headlong at a generation that is so un-churched it has no appreciation for the good religion can produce (though it knows a litany of religion's mistakes). Whether or not another political decision to issues that are moral if not spiritual is debatable.