President Donald Trump tweeted on Tuesday that getting rid of state lines would promote competition in the new GOP health care plan, and CNBC's Jim Cramer agrees.

"That would promote competition — getting rid of state lines, having different organizations go up against each other. There wasn't enough competition [under Obamacare], and it's one of the reasons why the rates went up so much," Cramer said on "Squawk on the Street" Tuesday.

@realDonaldTrump: Don't worry, getting rid of state lines, which will promote competition, will be in phase 2 & 3 of healthcare rollout. @foxandfriends

U.S. markets opened lower on Tuesday after congressional Republicans revealed late Monday their new plan to repeal and replace Obamacare.

Investors are also looking at the probability that the Federal Open Market Committee will approve a rate increase at its March 14-15 meeting.

The Dow Jones industrial average slipped .13 percent, while the declined .24 percent. The Nasdaq dropped .11 percent.

— CNBC's Berkeley Lovelace contributed to this report.