Support for vouchers, which would let parents spend public education dollars on private school tuition, has been tenuous in the House and in the public, where opinions appear split, at best.

Parents for Choice in Education, a pro-voucher political action committee, has purchased mobile billboards that drive daily around the Capitol and downtown. And House Speaker Greg Curtis, R-Sandy, has been grilling his colleagues to gauge support.

"Those in the middle, privately I've talked to them and undoubtedly they felt some pressure," Curtis said Thursday. "I think I've got the votes, I think I've got 38 votes."

A minimum of 38 votes in the House and 15 in the Senate are required to pass legislation.

Parents for Choice spokeswoman Nancy Pomeroy said the group first tried to buy ads on Utah Transit Authority buses. But UTA policy has barred noncommercial or political ads since at least 2003.

"This has absolutely nothing to do with their message," spokesman Justin Jones said. "I think people would say we leave money on the table, but the fact is we're not interested in advertising political messages."

So the PAC turned instead to the mobile billboard truck, which ended up being cheaper, Pomeroy said.

Starting this week, four different ads will rotate on the truck, which drives a loop between the Capitol and 400 South.

Now that the bill has been formally introduced, legislative debate won't be far behind. Rep. Steve Urquhart, R-St. George, who sponsored this year's bill, posted it on the Internet on Tuesday and asked for public comment.

Inside the House, supporters hope to have a quick debate and vote without a lengthy amendment process resulting in "death by a thousand cuts," Curtis said.

"We'll probably say, 'That's the bill, vote it up or down,' " he said. "I don't want to go out and have a contentious floor fight if the votes aren't there. . . . I will not put it out there on the floor unless I have 38 votes."