On Jan. 20, 2017, President Trump proclaimed in his inaugural address to a dumbfounded nation, “Together, we will make America great again.” Republicans greeted Trump’s promise with great enthusiasm, believing they would easily enact a policy agenda over the next two years to deliver on it. And why not? They controlled both houses of Congress and the presidency for the first time in more than a decade. Moreover, Trump’s proclamation was the perfect rallying cry for Republicans. In four short words, “make America great again” conveys the essence of their professed conservatism — looking to the past for guidance in the present on making progress in the future.

While restoring America to what Republicans see as its past greatness no doubt takes time, the explicit grandeur of their effort should at least be observable in Congress. Passing tax reform was indeed a start, as has been the Senate’s record in confirming Trump’s judicial nominees. However, the tax code is not the only problem people are concerned with at present. And notwithstanding Majority Leader Mitch McConnell’s, R-Ky., boasts to the contrary, the Senate is more than a Human Resources department for the federal judiciary.

In reality, we have a hard time seeing the effort in Congress to make America great again because it isn’t there. Most Republicans would likely to acknowledge, at least privately, that even with their new tax law and successful record of judicial confirmations, their legislative accomplishments to date have not measured up to their initial expectations.

Republicans should resist the urge to move the metaphorical goalposts before Election Day. They should instead ask themselves why things turned out differently than they expected. The answer may surprise them.

There is a straightforward explanation for the Republican Party’s collapse in Congress. Republicans were unprepared to enact a robust policy agenda that would make America great again because they could not remember what they believed made it great in the first place. If Republicans want to escape their current predicament, they must do more than pay lip service to the intellectual tradition that their professed conservatism embodies.

And they should be reading Russell Kirk. Born 100 years ago on Friday, Kirk was one of the leading conservatives in postwar America and did more than anyone else to revive the tradition Republicans ostensibly want to conserve.

Before Kirk published his magnum opus, “The Conservative Mind,” in 1953, Americans did not see conservatism as a respectable intellectual tradition. Lionel Trilling, at the time one of the nation’s leading intellects, declared, “In the United States … liberalism is not only the dominant but even the sole intellectual tradition.” In Trilling’s opinion, conservatives conversed “in irritable mental gestures which seek to resemble ideas.” Kirk agreed with Trilling in part; he originally wanted to call his book, “The Conservative Rout.”

Of course, we now know that conservatives were not in danger of being routed. If anything, they were on the cusp of a massive offensive that would push liberalism back from society’s commanding heights, in large part thanks to Kirk. “The Conservative Mind” helped transform conservatism from a marginalized strain of thought into a respectable intellectual tradition, capable of competing with liberalism for influence in American politics. The ideas Kirk highlighted in the book informed Republicans’ efforts as they helped to win the Cold War and end decades of Democratic control of Congress. In doing so, Republicans changed how millions of Americans thought about the federal government, and their legislative victories spurred unrivaled growth and prosperity throughout the 1990s. No less significant, conservative Republicans revived a long-dormant originalist understanding of the Constitution in the federal judiciary.

Not bad for a bunch of “irritable mental gestures.”

So what happened? Once capable of grand efforts, many of today’s Republicans appear uninterested in expending the effort to do big things.

The origins of the Republican Party’s present predicament can be traced to the period when postwar conservatism was at the height of its success. While conservatives have always been divided, they mostly agreed in the 1950s to put their theoretical differences aside to defeat communism abroad and stem the tide of democratic socialism at home. Yet the fall of the Berlin Wall in 1989 and the Soviet Union’s subsequent demise deprived conservatives of the glue that had held them together for decades despite all of their differences. Without the communist threat, democratic socialism proved to be insufficient for uniting conservatism’s disparate factions. Consequently, the conservative movement — as well as the Republican Party that is its home — has been plagued by divisions and infighting ever since.

Making matters worse, their 1994 takeover of Congress prompted many Republicans to prioritize questions of public policy and electoral politics over working through the issues over which they were divided. Republicans instead chose to de-emphasize those issues and rehash old verities while crafting an inoffensive policy agenda they could use to win elections. Somewhere amid the countless internecine battles, autopsies, purges, and reinventions, Republicans lost sight of what it was that they were trying to conserve in the first place. Consequently, they failed to update their intellectual tradition where they needed to account for the emergence of new problems in a rapidly changing world.

To be fair, Republicans are not alone in their present intellectual confusion. The Democratic Party also appears adrift, unwilling, or unable, to chart a consistent course toward the future because of the electoral uncertainty doing so entails. In fact, decades of intellectual suppression in both parties is responsible for the present political dysfunction.

Nevertheless, the status quo is particularly damaging for Republicans. Once unmoored from tradition, Republicans forgot about the intellectual heritage that made their prior successes possible. When that happened, the idea of intellectual conservatism inside the Republican Party quickly became a caricature of itself. That made it possible for Republicans to campaign as conservatives while governing as anything but conservative.

In the year after “The Conservative Mind” appeared, Kirk wrote, “Tradition cannot suffice to guide a society … if it is not understood and expounded and, if need be, modified by the better intelligences and consciences in every generation.” Republicans must remember their tradition and recover their disposition to conserve it.

Fundraising, message-testing, and get-out-the-vote efforts are no substitute for the power of ideas . No matter what happens in November, Republicans in Congress will remain unable to enact an agenda if they continue to ignore the ideas on which that agenda is supposedly based.

James Wallner (@jiwallner) is a contributor to the Washington Examiner's Beltway Confidential blog. He is a senior fellow at the R Street Institute. Previously he was a Senate aide and a former group vice president for research at the Heritage Foundation.