Joe Kennedy vs. Charlie Baker for governor in 2018?

Governor Charlie Baker (left) and Congressman Joe Kennedy III.Left: David L. Ryan/Globe Staff; Right: Kayana Szymczak for the Boston Globe

Governor Charlie Baker, he of a 70 percent job approval rating and plaudits from just about every top pol across Massachusetts, has long been riding high despite being a Republican in a blue state. Political operatives of both parties expect him to cruise to victory in 2018, should he run for re-election.

But a new poll shows there’s one Democrat who might be able to bring him down to earth. And of course, that official’s last name is Kennedy.

In a hypothetical 2018 gubernatorial matchup, US Representative Joe Kennedy III — a member of the famed Bay State political family — is tied with Baker 33 percent to 33 percent, with 29 percent unsure. That’s according to a UMass Amherst/WBZ survey of about 400 registered voters released this week.

Other Democratic officials, including Mayor Martin J. Walsh of Boston and Attorney General Maura Healey, don’t match up nearly as well the poll. Baker takes 43 percent to Healey’s 25 percent in the imaginary head-to-head. A Baker-Walsh matchup gives Baker 37 percent to Walsh’s 28 percent.

Said one-time Ted Kennedy aide and current Democratic consultant Scott Ferson: “It’s good to be a Kennedy.”

Baker, who has a whopping $4 million in his campaign account, told reporters Monday he hadn’t made up his mind on a re-election bid.

Kennedy is expected to stay in federal office and run for US Senate when one of the two Massachusetts seats opens up. But in Massachusetts politics, anything can happen.