Barack Obama lost Kentucky in 2012 by 23 points, yet the state remains closely divided about re-electing the man whose parliamentary skills uniquely qualify him to restrain Obama’s executive overreach. So, Kentucky’s Senate contest is a constitutional moment that will determine whether the separation of powers will be reasserted by a Congress revitalized by restoration of the Senate’s dignity.

Even counting Justice Louis Brandeis as a Kentuckian – at 18 he defected to Harvard and New England – Mitch McConnell, 72, is second only to Henry Clay as the state’s most consequential public servant. McConnell’s skills have been honed through five terms. He is, however – let us say the worst – not cuddly. National Review has said he has “an owlish, tight-lipped public demeanor reminiscent of George Will.” Harsh. But true.

On only one significant matter – McConnell opposes increasing the minimum wage, a symbolic issue of negligible economic importance – is he at odds with a large majority of Kentuckians. Thus he surely would be leading by more than a few points if he were less austere and more telegenic.

Democrats selected McConnell’s opponent, Alison Lundergan Grimes, 35, Kentucky’s secretary of state, largely to further their “Republicans loathe women” fable. McConnell, however, is running even with Grimes among women, partly because of the persuasiveness of his wife, Elaine Chao, the longest-serving labor secretary since World War II (2001-2009).

In 1952, a Republican member of the Phoenix City Council, Barry Goldwater, defeated U.S. Senate Majority Leader Ernest McFarland. For the next 52 years, until the defeat of Tom Daschle, D-S.D., in 2004, no party’s Senate leader was defeated. But political polarization has increased leaders’ conspicuousness and vulnerabilities. McConnell, who in 2002 won with 65 percent, won in 2008 with just 53 percent.

Grimes’ cringe-inducing campaign has depended on a migraine-inducing argument: She broadly disagrees with her party’s leader, but it is important that she help perpetuate Harry Reid’s iron-fisted shutdown of the Senate for Obama’s convenience. Her campaign has raised more money than McConnell’s in three consecutive quarters, but money is not magic, which would be needed to make her candidacy coherent.

Although Senate races in many states remain close – McConnell remembers Republicans losing control of the Senate in 1986 by about 25,000 votes in five states – he anticipates a Republican majority in 2015. Then, he says, “a lot of institutional repair” will begin.

Since Republicans won control of the House in 2010, the Democratic-controlled Senate’s function has been obstruction. Reid has prevented bills passed by the Republican House from coming to a vote, and has prevented Republicans – and Democrats, too – from proposing amendments to Senate bills that would be awkward for Democrats to oppose or for Obama to veto. Obama has cast only two vetoes, both for technical reasons on minor matters. Since July 2013, McConnell says, there have been only 22 Senate roll call votes on amendments – and says Alaska Democrat Mark Begich has never in his six Senate years had a roll call vote on an amendment of his.

Such paralysis of the Senate leaves Obama uninhibited in his use of executive orders and bureaucratic mission-creep to advance goals that should require legislation. Last January, in the most statesmanlike Senate speech in years, McConnell explained how, under Republican leadership, the Senate would be restored as the creator of consensus:

“An executive order can’t [create consensus]. The fiat of a nine-person court can’t do it. A raucous and precarious partisan majority in the House can’t do it. The only institution that can make stable and enduring laws is the one we have in which all 50 states are represented equally, and where every single senator has a say in the laws that we pass.”

Beneath McConnell’s chilly exterior burns indignation about the degradation of the institution to which he has devoted much of his life. The repair of it, in the form of robust committee and amendment processes – and an extended workweek – will benefit Democratic members, too.

Kentucky’s Senate election is 2014’s most important, for a reason rich in irony: Although Grimes considers McConnell the architect of gridlock, electing her to inevitably docile membership in Reid’s lockstep ranks would perpetuate this. But a re-elected McConnell, with a Republican majority, would, he says, emulate his model of majority leadership – the 16 years under a Democrat, Montana’s Mike Mansfield. He, like McConnell, had a low emotional metabolism but a subtle sense of the Senate’s singular role in the nation’s constitutional equilibrium.

© 2014, Washington Post Writers Group