Marc Elrich (center), Montgomery County executive, at a hearing in Rockville, Md., on Jan. 15. (Cheryl Diaz Meyer/For The Washington Post)

AS A candidate last year for the top office in Maryland’s largest locality, Marc Elrich often said there was no money in Montgomery County’s tight budget to make a big dent in many top priorities. Yet Mr. Elrich, a Democrat whose campaign for county executive was fueled by tens of thousands of dollars in donations from Montgomery’s public employee unions, found funds in his first proposed budget to support immediate and sizable pay increases, in many cases approaching 10 percent, for thousands of county workers represented by those unions — a commitment that recent history suggests is unsustainable.

Mr. Elrich, who took over labor negotiations upon entering office in December, cannibalized tens of millions of dollars earmarked in the current budget for future retiree health care to provide this bouquet of roses for his union backers, who take public credit for his razor-thin victory in the Democratic primary. The cost: nearly $29 million for the fiscal year starting this year, and almost $40 million annually after that.

Mr. Elrich’s contracts are a stroll down memory-impaired lane. It was less than a decade ago that his predecessor, Isiah Leggett, reeling from plummeting revenue in the Great Recession’s wake, was forced to abandon overgenerous pay increases he had negotiated. Mr. Elrich, at the time a county council member, had a ringside seat to the political turmoil triggered by the salary rollbacks. Now he risks a rerun unless the county council intervenes to insist on a more responsible course.

Mr. Elrich has opposed a property tax increase, mindful that the last one, just three years ago, was deeply unpopular. Yet barring such an increase, it will be difficult to pay for his fat labor contracts in coming years. Raiding the retiree health fund, already massively underfunded, is a bad idea that digs a deeper hole for decades to come. Mr. Elrich has hinted in the past that he might divert money from the county’s reserve fund, but doing so would imperil the county’s pristine credit rating and threaten sharply higher borrowing costs.

The proposed pay raises, which range from 9.4 percent for most government agency workers to 7 percent and 5.9 percent, respectively, for police and firefighters, are based on the bizarre logic that employees are somehow owed money for scheduled raises that were scrapped after the recession. In fact, public and private-sector salaries took a post-recession hit nationwide, and virtually nowhere was it assumed that employees would be “paid back.”

The county’s highly capable workforce deserves decent pay and benefits. Taxpayers are also entitled to consideration. If Mr. Elrich’s pay increases are approved by the county council, they guarantee that tens of thousands of teachers and other school workers, whose contracts expire next year, will seek equally hefty raises. That means a spiral of rising costs even as concerns mount that Montgomery’s job creation and business climate are anemic.

Mr. Elrich is playing a shell game with Montgomery’s finances. Council members, who control the purse strings, are not bound by his profligacy. They can and should ask tough questions about how the county can afford it.