MONTPELIER — Tuesday marked the beginning of another 10-day ad buy for Republican gubernatorial challenger Randy Brock, who will spread about $70,000 among three network TV stations to reach into living rooms across Vermont.

His message to voters this time: Gov. Peter Shumlin’s single-payer health care plan “will result in the largest tax increase in Vermont history.”

The 30-second spot opens with Shumlin himself announcing the birth of single-payer on the steps of the Statehouse. But a cautionary female voiceover soon warns viewers that all is not as well as Shumlin would have you believe.

“Wondering how this is going to work? Higher taxes, reduced choice, price controls, rationing of service, doctors leaving,” she says.

In what seems to be the formula for Brock’s autumn ad rollout — a 10-day run of commercials knocking Shumlin’s handling of the economy just expired — the second half of the spot turns the camera’s focus away from the Democratic incumbent and onto the Republican challenger.

“And we don’t know how we’re going to pay for it. We don’t know the effect that it will have on our providers,” Brock says. “And we know in all likelihood that it will result in the largest tax increase in Vermont history.”

For a guy with only about $240,000 on hand as of Sept. 15, Brock is hitting the airwaves pretty heavily. He has spent $140,000 now on 20 days worth of ads and told reporters Monday that he had not loaned his campaign any more money.

Either the Brock camp has ratcheted up its fundraising pace considerably, or the well is nearly dry.

Shumlin, meanwhile, has yet to spend a dime on television, and campaign manager Alex MacLean has declined to say when, or even if, they’ll go on the airwaves.

Shumlin had nearly $900,000 in cash on hand as of Sept. 15. At the rate he’s spending, he may well have a seven-figure war chest. On the day after the election.