Larry Kudlow‘s latest column at Human Events offers no kind words for Democratic presidential frontrunner Hillary Clinton’s tax proposals.

The worst sectors of the worst recovery since World War II are business investment in new plants and equipment and new business start-ups. These are the biggest job-creators, and their slump is a key reason for the sub-par labor recovery, with low participation rates and high numbers of involuntary part-time workers.

So if investment is the problem, what does Hillary Clinton go out and do? She proposes jacking up the tax on investment. It’s almost inconceivably stupid.

In her latest economic speech, Clinton proposes doubling the capital-gains tax rate on the profit made from asset sales (stocks, bonds, real estate) held a day less than one year up to two years. Right now, if you take a capital gain a day more than one year, you are taxed at a 20 percent rate. Actually, it’s 23.8 percent when you include the health-care surtax. So under Clinton’s brilliant new play, you’d be taxed at 43.4 percent — the top individual cap-gains rate of 39.6 percent plus the 3.8 percent Obamacare surtax.

That means, instead of keeping 80 cents on the additional dollar of profit, you’d only keep 56.6 cents — a 30-percentage-point reduction in the take-home-pay reward for taking an extra dollar’s investment risk.

This will create a tall barrier to investment — what we don’t need. If you tax something more, you get less of it.

Clinton complains about too much “short-termism” in the economy. But her program might well create more of it. That’s because she has a sliding tax-rate scale, whereby assets held two to three years would be taxed at 39.8 percent and assets held three to four years at 35.8 percent. And you don’t get back to the statutory 20 percent cap-gains rate unless you hold an asset for six-plus years.

Who’s going to lock themselves into that? What if new investment opportunities arise? Want to convert your current holding into cash so you can invest in your brother-in-law’s start-up? Maybe it’s the next Facebook. Who knows? The point is, the Clinton plan exacts a huge tax penalty on the movement from old capital to new.