Does Donald Trump's character matter to conservatives? It should. But it often seems it doesn't.

In the 1990s, conservatives argued against Bill Clinton by saying "character counts." The argument was rooted in Biblical principles that only solid and godly men should hold the grave responsibility of exercising authority for the community. A man who could not govern himself was not fit to lead others.

Conservatives (and some moderates and liberals) produced a raft of statements calling on Bill Clinton to resign over his adultery, or for Congress to remove him from office. One such statement, signed by many academics and scholars, read in part:

We are aware that certain moral qualities are central to the survival of our political system, among which are truthfulness, integrity, respect for the law, respect for the dignity of others, adherence to the constitutional process, and a willingness to avoid the abuse of power. We reject the premise that violations of these ethical standards should be excused so long as a leader remains loyal to a particular political agenda and the nation is blessed by a strong economy. Elected leaders are accountable to the Constitution and to the people who elected them. By his own admission the president has departed from ethical standards by abusing his presidential office, by his ill use of women, and by his knowing manipulation of truth for indefensible ends. We are particularly troubled about the debasing of the language of public discourse with the aim of avoiding responsibility for one's actions. [Moral-Crisis]

One of the signatories of the above statement was the Calvinist theologian Wayne Grudem. Grudem is the author of a highly regarded book of systematic theology in the Reformed tradition of Christian thought. He has also spent recent years venturing into writing on political issues.

Last week, he authored a long and detailed case for the moral responsibility of Christians to vote for Donald Trump.

Now, Grudem's influence can be overstated. His arguments are less likely to move evangelical voters than they are to simply be the most articulate expression of a representative evangelical sentiment. But it is nonetheless important to explore.

Grudem admits that Trump is "flawed," and says extreme things. Grudem concludes, however, that "most of the policies he supports are those that will do the most good for the nation." He further asserts that any action short of voting for Trump, Hillary Clinton's principal antagonist, amounts to supporting Clinton.

It's an interesting argument. But it seems to militate against the statement he signed in 1998, which said that "the moral character of a people is more important than the tenure of a particular politician or the protection of a particular political agenda."

It could be that Grudem doesn't really believe most of the issues at stake in 2016 are purely political. Grudem may think a properly political issue is something like taxes or welfare programs, and that Bill Clinton's presidency threatened fundamental values that should remain outside of politics. Grudem rightly points out all the ways that this election is important to Christians. The vacancy on the Supreme Court must be filled, and progressive justices seem newly anxious to overturn any legal restrictions or regulations that touch abortion. Progressive justices are newly hostile to religious liberties as they have been exercised by business owners and even religious organizations. Soon they will even be hearing cases that seek to force religious health-care institutions to perform abortions on their premises.

But Grudem's case for trusting Trump is not very persuasive. He simply asserts that the "most likely" outcome is that Trump would not renege on all his campaign promises, so voters have to assume he will follow through on them.

There are serious problems with this argument. The first is that most modern politicians commit to their political identity over a lifetime, whereas Trump has changed his political identity several times. And his change on abortion politics was the least convincing part of his transformation.

Another problem: One of Trump's few proven and consistent traits is making whatever outlandish promises he has to make to close the sale, and then leaving his creditors and business partners in the lurch later. He creates scam businesses, and he does so by selling his marks on a fantasy. Come to Trump University and become a real-estate billionaire. Finance Trump Taj Majal with junk bonds, and I'll save Atlantic City. I'll sign your pledge, but I won't be held by it. Make me president, you'll get four more Scalias. Subject to terms and conditions, of course.

Grudem's argument for Trump only makes sense if you make a strong effort to avoid the evidence about what kind of man Trump is. Trump has been serially unfaithful to his wedding vows, to his creditors, to his political personas. He doesn't just back away from extreme positions, he runs away from his campaign promises even during the campaign. The one believable statement Trump has made about himself is that he "doesn't bring God" into his life such that he would ask for forgiveness for his sins.

If Trump were not married, Grudem would surely not approve of him courting one of his daughters. If the local public school superintendent spoke about the size of his genitals on a public stage the way Trump did on a Republican primary debate stage, Grudem would seek to have that man removed from his office.

Why would he trust such a man with the grave causes that he believes are at stake in this election?

And what does it say about the quality of our convictions if we argue in 1998 that "the moral character of a people is more important than the tenure of a particular politician or the protection of a particular political agenda," but then, as soon as our political agendas are threatened, find a handy excuse for installing a "flawed" man in the same office? It says that our convictions come with a political out-clause.

But I'm not an expert. I suppose it takes a celebrated systematic theologian to construct an argument so dizzying that you temporarily forget the words that are printed in red letters: By their fruits, you shall know them.