Could Snohomish County’s battle against a heroin epidemic crimp Sound Transit’s delivery of light rail into Everett and other Puget Sound communities?

It may depend on voters’ tolerance for taxes, especially those living in south Snohomish County.

A measure on the August primary ballot would increase the sales tax countywide to generate millions of additional dollars for law enforcement agencies and criminal justice programs.

Then, in November, the Sound Transit 3 proposal will be in front of the electorate in Everett and cities in south county. ST3 would hike a trifecta of taxes — sales, property and motor vehicle excise taxes — to raise billions of dollars for expanding light rail and bus service in the next quarter century.

Those behind each measure have polling data showing theirs can pass. But they’re certainly worried about losing support from the Snohomish County electorate as each campaign gets into gear.

Strategists for the ST3 measure reportedly talked with a handful of Snohomish County leaders about holding off on the justice tax.

The transit proposal is going to be a tough sell in Snohomish County and it only gets tougher if voters’ tolerance for tax measures is sapped by the time they receive their November ballot. Don’t forget many of them also voted on boosting the sales tax for Community Transit last November. That means three significant tax hikes in a year.

Snohomish County Council member Brian Sullivan said action had to be taken to deal with the drug problem and rising incidents of property crime.

“This is a huge issue. There are those who will try to couch it as public safety versus public transit,” he said. “That certainly is not our intent.”

The County Council wanted their measure in front of voters in August specifically to avoid sharing the ballot with Sound Transit this fall.

A similar political conversation occurred in 2008. The County Council voted to put a $163.2 million tax package to redo and expand the courthouse on that year’s November ballot.

But Aaron Reardon, then county executive, vetoed it as too costly. Sullivan said another reason was that the Sound Transit 2 proposal was on the ballot and Reardon felt the county measure might mess things up.

Some think the inclination of the Snohomish County electorate to back the justice tax could be negatively affected by debate on ST3.

This theory assumes so much attention will be paid to the transit proposal that the word won’t get out on the purpose of the county measure and it will fail.

Right now, it’s pretty much guesswork.

Christian Sinderman, a veteran political consultant who is managing the Sound Transit 3 campaign, is optimistic, as one might expect.

“Any time there are multiple tax measures on the ballot there’s going to be concern,” he said. “But voters have a long history of supporting services they value.”

That theory will certainly be tested this year.

Political reporter Jerry Cornfield’s blog, The Petri Dish, is at www.heraldnet.com. Contact him at 360-352-8623; jcornfield@heraldnet.com and on Twitter at @dospueblos.