The reason that tax reform is going nowhere fast boils down to one word: Fear

President Trump has apparently scrapped his plan for tax reform and is starting over.

White House officials say it is now unlikely that they will meet the August deadline for tax reform set by Treasury Secretary Steve Mnuchin, according to the AP. The White House is also trying to learn from its mistakes on health-care reform, with White House officials more involved in crafting the legislation — not just leaving it up to Congress.

Scrapping the original tax plan is a good thing because many of the ideas there were considering were just plain bad. But as the White House and GOP re-work this policy, the White House and the GOP don't need to find new policies. They need to find some real backbone.

That's because the Republicans have spent the last five months proving that most of them don't have the guts to back the key conservative fiscal principles they supposedly stand for. Chief among them is the proven fact that cutting taxes spurs the economy and eventually raises tax revenues. A close second is the belief that smart budget cutting also boosts private sector investment and jobs.

Let's start with the tax-cutting argument, because it sure looks like House Speaker Paul Ryan, Ways and Means Chairman Kevin Brady, and some of their counterparts in the White House have forgotten the "Laffer Curve." The Laffer Curve is the theory developed by supply-side economist Arthur Laffer that explains that lower tax rates initially bring in lower tax revenues, but eventually lead to economic booms that more than make up for those early losses in more tax revenue collection.

If you look back at tax cuts enacted by Presidents Warren Harding and John F. Kennedy based on the same conservative argument, they ultimately resulted in greater federal tax revenue overall and a surging economy.

In fact, it was Kennedy who made the greatest courageous argument for this policy most people associate with Republicans only. In 1962, Kennedy said:

"In short, it is a paradoxical truth that tax rates are too high today and tax revenues are too low and the soundest way to raise the revenues in the long run is to cut the rates now."

In other words, JFK told us that cutting taxes was the road to economic prosperity. And when President Ronald Reagan sought to remind us of that wisdom when he became president, he instructed his budget staffers and speechwriters to use as much of Kennedy's blueprint and invoke JFK's name as much as possible in their planning and speech writing. Reagan's 1981 tax-cutting efforts came under intense criticism from Democrats, the news media, and a good number of Republicans in Congress as well. But Reagan's stalwart confidence and courage sold it to the country, with dozens of Democrats even voting for them in the end. The 1980s economic boom ensued.

Note that JFK and Reagan's plans never had anything in them about creating new taxes to raise revenues. The reason is they knew that new taxes wouldn't work. But intense fear of initial decreases in tax revenues seem to be the only reason why Ryan and Brady are so intent on that border tax on imported materials to "pay for those cuts." Of course, those new taxes will bring increased prices on consumers that will help to drive down tax revenues even further. This is an example of how political fear can lead to stupid choices.

Now let's talk about the spending cut side of this equation, because that takes even more courage. Reagan and JFK knew that you can't just start and end things with tax cuts. Indeed, the first year or so of a tax-cut regime will bring in less revenue. So they both pushed for reasonable spending cuts to go along with their tax reform plans.

Flash forward to 2017 and we have another example of cowardice from the White House and the Republicans in Congress when it comes to spending cuts. The Trump budget was filled with calls for discretionary cuts in small-potato items like PBS and foreign aid, but the real cuts and changes needed in defense, Social Security, and Medicare were nowhere to be found. And the concept that none of those three main drags on the budget can ever be tinkered with because the American voters will never tolerate it is bogus. In his definitive 2012 book, "The People's Money," pollster Scott Rasmussen showed in survey after survey that Americans will back major cuts and reforms to defense, Social Security and Medicare. They just have to be done as transparently and fairly as possible.

But it takes backbone to follow through with those kinds of reforms and cuts in the face of the inevitable backlash. A guaranteed avalanche of advocacy ads filled with pictures of elderly poor people and front page editorials in every mainstream newspaper bashing "Republican heartlessness" aren't easy for politicians to take when they see their careers measured solely by momentary swings in public opinion. Yet let me offer the one-word response most voters would give to elected officials who are fretting about making those hard choices: "tough." Or perhaps they'd prefer hearing the slightly longer lesson from President Harry Truman: "If you can't stand the heat, get out of the kitchen."

Why does anyone think it's the government's job to raise revenues anyway? Yes, cutting taxes will eventually raise revenues but that's not the main point. The main point is to let the private sector soar in a crazy idea the Declaration of Independence insisted on: "Life, liberty and the pursuit of happiness." The government's job is to get out of the way and prioritize its own spending, no matter how much of our money it's taking in every year. And speaking of that, the federal government is taking in a record amount of tax revenue so far this fiscal year. Washington doesn't need more revenue; it needs less spending.

Make no mistake. Border taxes and other schemes to suck more money out of the economy aren't sound new policy, they're evidence of political fear. So, too, are budget-cutting proposals that are barely a drop in the bucket. The reason why Republicans are getting nowhere fast on tax reform is because of fear. And other than President Trump's bold call to drastically cut corporate tax rates to somewhere between 15 and 25 percent, there is no other sign of courage so far. Until we see some of that courage, there won't be any political or economic success either.

Commentary by Jake Novak, CNBC.com senior columnist. Follow him on Twitter @jakejakeny.

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