The large infusion of House members into the Senate next year and the results of the primary election have set the stage for a showdown over one of the most powerful positions at the state Capitol: the Senate presidency.

At this point, none of the four Senate presidential hopefuls has a lock on the position.

It will be difficult to peg the legislative leadership races until senators and representatives are elected in November. After all, House and Senate leaders are elected by their respective caucuses in each legislative chamber.

But the primary election results gave a few hints about who might have the best shot at becoming the next Senate president. Political insiders are already making odds on the four contenders, even though most lawmakers hesitated to say whom they would choose.

Senate President Bob Burns will retire after this year, leaving the leadership post vacant.

“Individually, if they would stand right now, I think Russell (Pearce) has got more commitment, but he doesn’t have enough to lock it up,” said Sen. Frank Antenori, a Republican from Tucson, who said he hasn’t made up his mind who to back.

Those who have made it clear that they intend to seek the top spot in the Senate are Pearce, the author of SB1070; Rep. John McComish, the House majority leader; Rep. Steve Yarbrough, the House speaker pro tempore; and Sen. Steve Pierce, who has served as Senate majority whip and president pro tempore.

Yarbrough and McComish are hoping to switch chambers this fall; both are expected to win their general election races. But some senators are wary of a “House takeover” if either is chosen to lead the Senate.

Pearce has served 10 years in the Legislature and is regarded as one of the most influential members of the Senate. He now serves as chairman of the Senate Appropriations Committee.

But Pearce is viewed by some as a single-issue lawmaker who is fixated on illegal immigration. Some lawmakers and special interest groups have said they are concerned that Pearce’s immigration agenda would distract the Legislature from other priorities such as creating jobs and stimulating business growth.

And then there’s Pierce, who is finishing his first term in the Legislature and is the only Senate president hopeful who hails from rural Arizona, which could work for or against him when the leadership votes are tallied. He also has the shortest legislative track record among those vying for the job.

The Senate president is extremely powerful at the Capitol. Whoever gets the post could set the tone for the entire Legislature. The president, for example, has the power to advance or hold any measures that are introduced.

What makes the race even more interesting this year is the large turnover in the Senate. At least half of the 30 senators won’t be coming back to the chamber. Most of them are termed out. Meanwhile, 13 House members are running for election to the Senate this year.

At least three issues are expected to resurface as priorities in 2011 — the budget, job creation and illegal immigration — and some senators are evaluating their leadership options based on how they prioritize those issues.

Some lawmakers have said privately that they don’t want immigration to be a daily staple at the Capitol, and are therefore holding out to vote for someone other than Pearce.

Special interest groups, particularly business advocacy groups, argue that focusing too heavily on immigration laws would distract lawmakers from solving more pressing problems, such as the budget deficit and a struggling economy, and would dissuade, rather than attract, businesses and tourists.

The Arizona Chamber of Commerce and Industry, for instance, has said the Legislature needs to focus on the economy and move beyond immigration.

“In my opinion, we have reached our theoretical limit of what we can and should do,” said Glenn Hamer, the chamber’s president and CEO, referring to laws against illegal immigration.

Pearce said he would concentrate on fixing the budget, creating jobs, helping members pass their bills and advancing the Republican platform. Yet at the same time, he said the Legislature needs to pass more laws against illegal immigration.

After SB1070 was signed into law earlier this year, Pearce said he plans to author new legislation next year to end birthright citizenship and force the children of illegal immigrants to pay tuition to attend public schools.

“I’m not going to back away from what’s good for America and Arizona. I’m not going to back away from those issues,” he said, adding, “Unlike some, maybe, I can multitask.”

There are other undercurrents in the race for Senate president: Historical divisions between the legislative chambers and the candidates’ length of service in the Legislature.

Incumbent senators who are likely to return next year have said that they fear a situation where the Senate becomes an extension of the House, jeopardizing the Senate’s independence. For Yarbrough and McComish, that could prove to be a big hurdle.

In recent years, the House and Senate have battled over legislation to jumpstart the economy and especially over the state budget. Republicans have held a solid majority for years in both chambers, but differing philosophies between the majority caucuses has caused deadlock on some GOP priority measures.

Pearce and Pierce are trying to exploit that rift.

“It has never been done and it is inappropriate to come from the House to the Senate and want to be crowned king,” Pearce said.

“The incumbent senators who are already sitting there that are coming back, they’re not going to allow somebody from the House to come over and take over,” Pierce said.

Both McComish and Yarbrough are aware of the view, but dispute the idea of a House takeover.

“I have heard it several times, mostly from the Pierce and Pearce camps,” Yarbrough said. “(But) when we go to the Senate, we’ll all be senators, and I don’t think somebody is a two-star senator and somebody is a one-star senator.”

McComish said the two chambers have the same mission and nearly identical rules, which means leadership experience in one chamber is “very translatable” to leadership position in the other chamber.

Pierce, on the other hand, would have to overcome the perception that Senate presidents must be seasoned lawmakers who spend many years at the Capitol prior to assuming the top leadership role.

On rare occasions, second-term lawmakers have been elected Senate president.

John Greene, for instance, became Senate president during his second term in 1993. Greene, like Pierce, had no prior House experience.

In 1997, Brenda Burns became Senate president during her second term, although she had previously served in the House.

In some cases, the primary election results point to clear frontrunners in the races for leadership. This year, for instance, House Speaker Kirk Adams is expected to retain the top position in that chamber, and Rep. Andy Tobin is expected to jump to House majority leader from majority whip.

But the races for Senate leadership are much more complicated, and the primary results didn’t give any of the presidential candidates an insurmountable lead.

“The results were inconclusive,” McComish said.

Pearce, though, said he has crunched the numbers, and he is characteristically confident in his findings. He likely will see several of his longtime allies return to the Senate next year, and he claims to have more votes lined up than any other candidate for president.

“I probably have the votes at this point,” Pearce said. “And I only get stronger in the general (election).”

Steve Voeller, president of the Free Enterprise Club, said it’s meaningless to have the most commitments from fellow senators; what matters is having a majority.

The equation becomes even more difficult to solve when considering that none of the four president candidates is likely to gain a majority in the first round of voting for leadership positions.

“To me, that’s where this all breaks down,” Voeller said. “Even if you counted Russell (Pearce) having seven — and I don’t know if he does or not — but let us say he has seven and the House guy has six and Steve Pierce has five, it doesn’t really mean anything because (on the) first ballot nobody can win, and if everybody knows that going into it then you may see a deal try to get cut beforehand.”

The inside scoop on leadership elections

Republicans, who are expected to retain a majority in the Senate, usually hold an organizational meeting to select the Senate president, majority leader and majority whip immediately after the November general election.

Democrats will do the same, electing a minority leader, an assistant minority leader and a minority whip.

Republicans hold an 18-12 advantage in the Senate. If that spread stays the same after the general election, a candidate for president would need 10 Republican votes to win.

The voting in each caucus is done by secret ballot. If someone has a clear lock on a majority of the votes, they can be selected to leadership positions by acclamation. If the race is close, several rounds of voting may be necessary.

The Senate president is officially installed on the first day of session. By then, each caucus has long selected its leadership teams.