Investors who are formulating their 2020 strategies need to be cautious in case Sen. Elizabeth Warren ends up winning the presidential election, CNBC's Jim Cramer said Monday.

"A lot of business people are just terrified of her, and they're going to view everything she does through an extremely uncharitable lens," the "Mad Money" host said.

"So if Warren wins the [Democratic] nomination and the general, unless she immediately makes nice with health care, with banks and all sorts of other big businesses — don't bet on it — I think you'll want some cash insurance."

As for how the market might react to any other Democratic presidential candidate besides the Massachusetts progressive and Sen. Bernie Sanders, I-Vt., Cramer said it would be "neutral for the stocks, at worst."

That was the case under former President Barack Obama, who may have seemed "indifferent" to stocks but still oversaw a "terrific market, even if it started from a very low benchmark," Cramer said.