Since the 2008 crash the economy has been propped up with artificially ultra-low interest rates.

The financially regulators were unable to stop Wall Street criminality because they were owned by the big banks. Congress and the Presidency were unable to implement (or even consider) the badly needed reforms the economy requires because they were owned by the big banks.
So it all got papered over with cheap money, which propped up asset prices (specifically stocks, bonds, and real estate. aka things that rich people owned). Every time there was even a hint of danger to the markets, the Fed cut interest rates.
That flood of cheap money never made it down to the working class, but it did wonders for Wall Street.

Today that 12-year long con ended.

It was the first emergency rate cut coming in between scheduled meetings since the financial crisis, as well as the largest.

There is also the longstanding question of how effective monetary stimulus, and even some forms of fiscal stimulus, can be in the face of what is likely to be a “supply shock” — the type of economic hit caused by the absence of goods and services as the virus forces factory shutdowns and curtails transportation and travel. Monetary and fiscal stimulus is typically aimed at mitigating demand shocks, which are sharp cutbacks in spending by households, businesses or governments.
To the extent that policy makers can respond to the potential for an eventual demand shock, pressure will likely mount on politicians to provide a fiscal boost, potentially in the form of temporary tax cuts and other measures. That is even more the case outside the U.S., where major central banks, including the European Central Bank and Bank of Japan, have all but exhausted room for additional monetary easing, analysts said.

Another tax cut for the wealthy, really? We are on track to record the first $1 trillion deficit since 2012, and this is before a recession hits. And you want yet another tax cut for the rich?
Because let's face it, the rich are the only people Congress gives tax cuts, and “Only the little people pay taxes.”
Plus Trump has already stopped enforcing corporate regulations at an enormous cost to public safety.
So since relief for the working class is outside of the realm of possibility, what possible economic stimulus is left?

Totally serious: That the Federal Reserve is explicitly stating their job is to support the asset markets shows how unmoored to reality they have become. No price discovery? No fear of losing all credibility? No problem. That ship has sailed anyway. You guys are feckless.

— Dave Collum (@DavidBCollum) March 3, 2020

President Trump knows real estate, so interest rates can never be low enough.

"The Federal Reserve is cutting but must further ease and, most importantly, come into line with other countries/competitors. We are not playing on a level field. Not fair to USA. It is finally time for the Federal Reserve to LEAD. More easing and cutting!" tweeted Trump, who has long criticized the U.S. central bank and urged lower rates.

One thing Trump does not understand, besides empathy and personal sacrifice, is macroeconomics. Yes, interest rates can be too low.

A key indicator of the economy's growth hit a historic low on Tuesday, as the benchmark 10-year Treasury yield fell below 1%.

The yield fell to 0.993% as investors bought up safe-haven investments like Treasurys on fears the spreading coronavirus could slow the U.S. economy

Interest rates are already at all-time lows. So there is only so much more the Fed can cut.
Well, the Fed can go negative, right? It just so happens that Sweden, which went negative in 2014, raised interest rates back to zero today, while admitting that NIRP has been a failure.

The answer is that Sweden’s central bank has finally acknowledged what we were writing from the very beginning of the NIRP, i.e., that the costs of this policy outweigh the benefits, euphemistically speaking. Indeed, Riksbank admitted itself that concerns about the side-effects of the negative interest rates on the economy contributed to its decision. As we read in the minutes from the December meeting,

a long period of negative interest rates may have negative side effects on the economy, as the draft Monetary Policy Report commendably describes. This is a parameter that we should take into account.

It's looking more and more likely that the markets are going to dump by this spring/summer. At which time the entire political environment is going to change.
And the Fed won't be able to stop it this time.
We've already seen the fastest stock market plunge in history. Faster than 2008. Faster than 1929.