The "Laffer Curve" first came to public prominence back in the heyday of Reaganomics and "supply side" ideas. The concept is simple and, once you think about it, obvious (I say "once you think about it," because even though it's been around since the 14th century, it took Arthur Laffer to get people thinking about it).
What the Laffer Curve tells us is that the "optimal" tax rate t -- the rate which will produce the most revenue for government -- is less than 100%. There's a tipping point in tax rates beyond which people work less and produce less, creating less wealth to tax, than they otherwise would have. This is because they're not keeping as much of what they earn, making the earning of it less attractive. If the tax rate is x%, you get out of bed and go to work even if you have the flu; if the tax rate is x%+1, you take a sick day if you wake up with the sniffles, or maybe you pad your week of paid vacation out with a couple of unpaid days off on either side. The Laffer Curve treats that in the aggregate -- everyone's "tipping point" can be different, but there's still an overall tipping point at which increasing taxes would decrease, rather than increase, government revenues and vice versa.
One problem with the Laffer Curve as illustrated: 100% taxation would probably not produce zero government revenue. Even in the most complete state socialist system -- a system where every dime you earn goes to the government, which doles part of it back out to you in "benefits" -- some people would continue working right up to the minute the system was overthrown.
Anyway, here's the thing: Reaganites and other "conservative" politicians love the Laffer Curve because it allows them to promise tax cuts and maintenance of the welfare state. That's been the mantra since the 1980s: "We can cut taxes and still grow the federal budget -- our revenues will go up, not down, because we're on the right side of the Laffer Curve!" This is a great way to sell tax cuts (and the politicians who promise them) to those who are directly employed by government or who depend on a government check, a government contract, etc. for their livings.
BUT!
Reducing the size, scope and power of government is a worthwhile end aside from the issue of how heavy the tax burden is. Increased government revenues are a bad thing, because most of what government gets up to is mischief of one sort or another.