PHOENIX — State lawmakers — all of whom are Republicans and Democrats — are moving to make it harder for the candidates from other political parties to run for office.

On the surface, HB 2608 changes the computation used to determine how many signatures are needed to get nominated. Right now it is one-half of one percent of eligible voters; this changes it to one-fourth of a percent.

But the fine-print detail changes who are “eligible voters” who can sign the petition. The measure, which was already approved by the House, received preliminary Senate approval Tuesday.

Under current law, that figure is based on the number of people registered with each political party. So for Republicans wanting to run for statewide office, that means 5,570 signatures.

The new formula, however, requires the computation to be based not just off the number of party adherents, but also political independents.

That’s not a big deal for Republicans, with the one-quarter percent of the new total coming up at 5,707.

For Libertarians, however, the story is totally different.

With just 27,706 registered with the party, it takes just 139 signatures for someone to get nominated to run for statewide office. But adding the independents to the calculation moves the requirement up to 2,987 names.

Sen. Steve Yarbrough, R-Chandler, said the change makes sense because existing law already permits candidates to get signatures not only from members of their own party, but also independents. And the 1,167,083 independents — 36 percent of total registration — outnumber those affiliated with any political party.

But Barry Hess, who has run for governor on the Libertarian Party ticket several times, said this is just another effort by the major parties — and the Republicans who control the Legislature in particular — to keep candidates from his party off the ballot.

Yarbrough conceded: “What we have is that people who have historically been third-party candidates” have “been able to get on the ballot with an incredibly small number of signatures,” even though they have access to all those independents.

And Rep. J.D. Mesnard, R-Chandler, who is sponsoring the legislation, conceded two years ago, in pushing virtually identical legislation, his real goal is creating an easier path for GOP candidates to win.

He argued in 2013 that people try to “manipulate the outcome of elections by putting third-party candidates on the ballot” since all they need is a minuscule number of signatures.

Hess said Republicans are sadly mistaken if they think keeping Libertarians out will result in the election of more GOP candidates.

“They really are so small-minded as to think that Libertarians are just going to vote for anybody, a lesser evil,” he said.

Hess said if Libertarians can’t get their candidates on the ballot the regular way, they will write in names rather than simply vote for someone whose name is on the ballot.

“There is no good Republican, there is no good Democrat,” Hess said.

A voter-sponsored referendum to block the 2013 legislation, which also had other changes in voting laws, led to legislators repealing that measure last year.

HB 2608 resurrects this key provision from that bill.

Follow Howard Fischer on Twitter at @azcapmedia.