After suffering one humiliating failure after another this year, Republican lawmakers are attempting to get their agenda back on track with a campaign to cut taxes. But once again, they may find in Donald Trump a less-than-effective advocate for their goals. Not because Trump’s views are inconstant—though they are. Not because Trump is a fair-weather friend—though he is. No, Trump may prove a liability on tax reform because he exposes, more clearly than ever before, the fantasy that undergirds the Republican approach to the economy. Indeed, not since Teddy Roosevelt has the GOP had a leader whose views are more corrosive of the virtues of money and the value of markets.

Already, Republicans have all but abandoned one of their traditional hobbyhorses: the need to reduce the debt and the deficit. Despite the fact that the GOP tax plan would add some $2 trillion to the national debt, Republicans have barely batted an eye. The truth is, being in the red is something the GOP raises concerns about only when Democrats are in power, as an argument against spending on social programs. “It’s a great talking point when you have an administration that’s Democrat-led,” GOP Representative Mark Walker said recently. “It’s a little different now that Republicans have both houses and the administration.”

The other justification Republicans offer is what John Kenneth Galbraith called “reactionary Keynesianism.” Cutting taxes, the argument goes—particularly at the high end—will put money into the hands of the investor class, who will use that money to create jobs and grow the economy. Today, it’s harder than ever to swallow this argument. The main effect of tax cuts since Ronald Reagan has been to increase inequality, not growth. Capital is now swimming in capital; were an influx of cash to the one percent all that the economy needed to grow, we’d have seen a massive increase in GDP over the last decade. Even figures like Bruce Bartlett, who helped promote the idea of supply-side economics as a domestic policy adviser to Reagan, has since renounced the theory. “Virtually everything Republicans say about taxes today is a lie,” Bartlett asserted recently.

But there may be an even deeper problem with this argument: Trump himself. The reactionary Keynesian believes government should put cash into the hands of the investor class because they are the most talented, visionary, and worthy. We know they are worthy because they are rich; the market wouldn’t have rewarded them if they weren’t deserving of reward. Markets discipline everyone, the idea goes, imposing obstacles and challenges that only the very best can overcome. But Trump tells a completely different story.

Trump, it hardly need be said, is no critic of capitalism. He champions property and profit, and celebrates wealth—especially his own. Capitalism is more than an economic system for Trump. It is a space of revelation, the place where men announce and disclose who they are—winners and losers, successes and failures. “The dollar always talks in the end,” Trump writes in The Art of the Deal, still a kind of Rosetta Stone to Trump’s rise and rule. What men make of themselves in the market, and what the market makes of them—these are the things that matter about capitalism. It is the consummate mode of identity politics, the ultimate truth-teller.