It is no longer a fresh story, but the selection of Paul Ryan as vice-presidential nominee by Mitt Romney is the most, and possibly the first, presidential act W.M. Romney has taken. After doffing his cap in every ideological and policy direction for his entire six-year charge at the Republican presidential nomination, and appearing throughout to be a conviction-free consultant whose answer to everything was a promise to look at the data and assemble the experts and trust in freedom and a cascade of platitudes, he has alit on radical fiscal responsibility and taken the Obama administration on confrontationally.

Instead of waffling over the Obama effort to portray individual enterprise as the consequence of state spending and to demonize Governor Romney himself as an asset-stripping, tax-avoiding job-outsourcer, while the administration ran for cover on the deficit and muddied the waters with a red herring about soaking the wealthiest 3% for the benefit of the suffering 97%, Mr. Romney has drawn the line in the sand on the greatest issue before the country.

WMR (a start has to be made somewhere to prevent the possible next president from being known to the world as a piece of athletic equipment) has addressed the two biggest concerns about his candidacy: that he was a consultant and not an executive, and that he had no serious plan or will to deal with the mountainous deficit piling up at $1.5 trillion a year with no sign whatever that the government has any intention of trying to deal with it. The choice of Paul Ryan should solidify Republican support and gather in even the loopiest tea-partiers.

Because Paul Ryan is eminently sane, he has laid out serious ideas to cope with the deficit and start to manage it downward — ideas that have so got under the president’s skin that Mr. Obama has reserved some of his grossest abuses of etiquette for the young congressman. He gave Mr. Ryan a treatment similar to that to which he subjected the Supreme Court: Both Mr. Ryan and the justices were invited, front-row listeners to presidential addresses in which the president abused them to their faces and misrepresented their positions.

Of all the possible presidential candidates for the Republicans, those who seemed to possess a clear idea of the nature of the present crisis and to possess a well-thought-out idea of what America is and must be were Paul Ryan, Jeb Bush, Mitch Daniels, Marco Rubio, Haley Barbour, and Chris Christie (though, in Governor Christie’s case, the U.S. should show extreme caution in elevating any alumnus of its rabid prosecution service, especially from such a rancid state as New Jersey, to the highest offices). As many, including me, have commented with concern, although WMR did not make that cut, he won the nomination anyway, and none of those who seemed to be better qualified intellectually and in policy terms sought the office.

Mr. Romney appeared to be a faction of his own that wished to fudge the issues, avoid controversy, and sail through the election on his back foot, fending off the febrile assault on his character by the incumbent. This crude smear campaign seemed to hit bottom last week as Romney was accused by a Democratic PAC of effectively causing the death of a woman from cancer. This is scraping the barrel with a squalor that normally backfires, although the Republicans have not responded as energetically as they should have.

The offensive television ad, and the president’s failure to disavow it, may indicate some desperation in the Obama entourage, and cannot be helpful to the inexplicable levitation of his generally high marks as an affable chap, which is a public-relations bumblebee that has defied all norms of public-personality assessment. (There was already, however, starting to creep in the impression that the president is replicating in domestic campaign travel the peripatetic fruitlessness of his secretary of state; that he is obsessively clinging to his office, while spending much of the rest of his waking hours chain-smoking and watching basketball on television.)

This sets the scene for a refreshing ideological contrast, on the scale of those of 1964, which pitted liberal Lyndon Johnson against conservative Barry Goldwater, and 1972, between centrist-conservative Richard Nixon and left-liberal George McGovern, and the 1984 election between Mr. Ryan’s political hero Ronald Reagan and Walter Mondale. Johnson, Nixon, and Reagan won by 16 million, 18 million, and almost 17 million votes: the country’s three greatest historic pluralities. McGovern and Mondale had promised tax increases. The Ryan budget, twice passed by the House under the leadership of the young congressman, would cut personal income taxes to a two-rate level of 25% and 10%, and corporate income taxes to 25%; it would farm Medicaid out in block grants to the states; and it would turn Medicare essentially into a voucher program to reinforce private-sector plans.

The Obama health-care plan would be repealed, and the stealthy abandonment of American international involvement implicit in the Obama administration’s defense-spending cuts and serene anticipation of funds sequestration would be avoided; and military spending would increase at the rate of inflation (not anticipated to be high). (Making the Ryan announcement in front of the majestic and historic battleship Wisconsin — which is named after Ryan’s home state, a swing state; and which is now a permanent memorial at Norfolk, Va. — was a fine touch.) The percentage of GDP represented by the national debt, which is now, depending on definitions, between 80% and 90%, would, over 25 years, decline to 10%, and the public-sector share of GDP would decline from 25% to about 18%.

In choosing Mr. Ryan, WMR has decided to make this an epochal policy election, in which the Romney-Ryan model of the enterprise state and the Obama approach — of an increased state share of the economy, soak-the-rich taxes, and the assertion that the person who builds a business doesn’t really build it but benefits from the generosity of the government in providing the conditions where enterprise can flourish — will exchange intense policy fire over the next twelve weeks. The mudslinging on which the Obama campaign has largely wasted about $150 million in the last three months will not set the tone of the campaign.

What was shaping up as a dismal avoidance of terribly serious issues may now be a fascinating battle. And in going for Mr. Ryan, Mr. Romney has leapfrogged the Republican flat-earth society typified by Speaker Boehner, who has trouble controlling his caucus and is a nervous and irresolute leader given to uncontainable tearfulness and compulsive chain-smoking. If Messrs. Romney and Ryan win, we may hope that Mr. Romney will give Mr. Ryan authority to oversee the budget process in the administration and Congress. Presidents can allocate tasks as they wish: James Madison had James Monroe as his secretary of state and of war simultaneously, to end the War of 1812 by force and diplomacy. (Which he did.)

There are a couple of other perspectives that have changed radically. Roman Catholics, 27% of the population, do not vote as a bloc, and the number that would be motivated at all by the presence of a co-religionist as candidate for vice president is probably not very high. But Paul Ryan is a practicing member of his faith who has already emphasized that human rights come from God and nature and not government, and blends his religious views seamlessly with his political program, in contrast to the Obama administration’s assault on the Roman Catholic Church, with its decree that it pay for the high-end contraceptive and sterilization needs of employees and students in Catholic institutions.

The Church has already served notice that it intends to caution voters (of all and no faiths) about the secularist aggrandizement of this administration. It is unfortunate but necessary, but as I commented here two weeks ago, the tradition, as old as the Republic, of respectful coexistence between the state and the churches has been premeditatedly attacked by this administration and will be an undercurrent of this election. The presence of a Roman Catholic as a Republican candidate for national office should pull whatever sting there may have been in the Mormon issue in respect to Romney.

Then there is the vice-presidential contest itself. As my learned National Review colleague Jonah Goldberg pointed out in that publication a couple of months ago, the incumbent, Joe Biden, has a brain that is a hot-air balloon. For a time, he performed the important national service of being all that stood between the president and Nancy Pelosi’s assuming that great office. But he is a harking back to the precedent of people like Charles Curtis, Henry Wallace, Spiro Agnew, and Dan Quayle, who were not really up to being president.

Mr. Ryan is cut from the cloth of those vice presidents who were, such as Harry Truman, Richard Nixon, Lyndon Johnson, and George H. W. Bush. There should now be a ding-dong battle between clearly different political options, rather than the Gong Show tawdriness of highlighting Romney’s dog on the roof of his car on the famous ride from Boston to Canada, and the work of the Democrats’ giggly snipers, such as Gail Collins and Maureen Dowd, plinking gleefully at “Hermanator” Cain, Newt “The Human Hand Grenade” Gingrich, Rick “The Armed Jogger” Perry, and the supposedly “Medieval” Rick Santorum. This could be, in what was once one of the current president’s most laudatory adjectives, a transformative election, beginning the renascence of America from its present parlous condition.

cbletters@gmail.com. From the National Review.