With the major indexes only points from record highs, one market expert warns that the unpredictable political climate could soon wreak havoc on stocks.

"I think [what's keeping stocks afloat is] earnings and a dose of optimism about what policies we're going to get from this administration," Rebecca Patterson, chief investment officer at Bessemer Trust, said Tuesday on CNBC's "Futures Now." "We're definitely discounting valuations, some deregulations, some fiscal stimulus, and our base case is that we are going to get those things."

According to Patterson, as long as President Donald Trump and Congress continue to press for tax reform and economic stimulus, a level of hope will remain in the market. "But anything we see that derails [those policies], a focus on the Supreme Court or Obamacare, that takes us away from stimulus for an extended period [could make the market] a little vulnerable to at least a tactical pullback," she added.

Patterson is particularly interested in Trump's meeting on Friday with Japanese Prime Minister Shinzo Abe, especially since the president scrapped the Trans-Pacific Partnership trade agreement. Patterson believes the markets could be in jeopardy, depending on how willing Trump is to build a trade partnership with countries like Japan.

"If you come out of that day and the rhetoric is more aggressive, non-consensus building, I think people will get more worried about this protectionist rhetoric," she said.

But ultimately, Patterson is most concerned with Trump's dealings with China, stating that a "trade war with China is going to end badly." China is one of the U.S.'s largest trading partners, and the market expert believes that butting heads with the Asian trading giant would lead her to reconsider her stance that the markets could rally higher.