Following Thursday's sell-off — the biggest one-day loss since 2020 — equity futures roil once again in response to China imposing retaliatory 34% tariffs on U.S. imports. As the VIX spikes above $40 and crude oil falls below $64 for the first time since 2021, Kevin Green assesses the damage. He says the downside support level for the S&P 500 (SPX) may fall to the $5,000 level, with a "far-fetched" upside of $5,500.