A lot of focus in Philadelphia’s primary election campaign has been on the 28 Democrats vying for City Council at large, particularly since two seats are open, meaning there will be two newcomers.

But the race on the Republican side could get interesting, too. The party isn’t endorsing any candidates for Council at large, and neither incumbent will be a lock.

How does the Republican Council primary work?

First a short — promise — primer on how Republicans get elected to Council. Only the at-large Council race is contested in the primary.

Step one: Get enough votes to be a top-five vote-getter in the primary. This year, seven Republicans, including the two incumbents, are vying for five nominations. Candidates are listed on the general election ballot in the order of votes received in the primary, so doing well means a better ballot spot in November.

Step two: Come in sixth or seventh in the general election. OK, coming in first through fifth would work, too, but in a city where Democrats far outnumber Republicans, it’s almost a foregone conclusion that the five Democrats who win the primary will be successful in the general election, and the two Republicans who trail the closest behind will join them on the fourth floor of City Hall.

That’s not to say an independent — several are running in November — couldn’t win one of the minority seats, though it’s never been done.

GOP isn’t endorsing anyone

The party has two incumbents, David Oh and Al Taubenberger, trying to keep their seats, but the GOP City Committee declined to endorse anyone in the primary.

“I was actually stunned by the fact they decided not to endorse,” said party Chair Mike Meehan, who is not a ward leader, so has no voting power on the committee. “To me, that was a little odd. It’s an odd year, to tell you the truth. We have seven candidates, each interesting in their own different way, and they’re all trying to hit their lottery ticket and try to get elected.”

Even more curious, Oh, 59, a ward leader himself, voted against endorsing candidates. Oh said he looked at a field that included four ward leaders who would almost certainly get party backing and didn’t want newcomers to be shut out.

“I thought it was a good idea that we not endorse the five old guys and give a chance to the new folks,” Oh said.

Meehan said that while he likes both incumbents, neither “is a lock.” He said some dissatisfaction with the incumbents could have played into the non-endorsement vote.

‘Sanctuary city’ a big GOP issue

While the majority of Philadelphians favor remaining a “sanctuary city,” Republicans are generally opposed. A recent Inquirer poll found 59 percent of registered voters approved of the policy. Seventy percent of Republicans polled thought it should change. And among GOP voters, immigration was the third biggest issue facing the city, after crime and taxes.

Oh and Taubenberger have both taken some flak on the issue. Both oppose Mayor Jim Kenney’s 2016 executive order barring city police from complying with detainer requests from Immigration and Customs Enforcement.

But when State Rep. Martina White (R., Phila.) introduced a bill to bar the city from state grant money, Oh responded with a resolution denouncing the threat.

“I’ve heard people say the mayor would have backed down, but to me, it’s about funding the city," Oh said. "In my role as an at-large Council person, it’s my job to make sure that in Harrisburg, they understand it’s not just Democrats who oppose the cutting off of funds — it’s also Republicans like me.”

Taubenberger, 66, has also been criticized by members of his party for a resolution he cosponsored that praised Kenney’s sanctuary city policy. He said it was his first Council session after he was elected and he wanted to show bipartisanship. “I’m also the child of immigrants, my parents both came over from Germany in the 1930s,” he said. “Now that we know what it’s like, I don’t [support the policy], but it was early on and I was trying to reach across the aisle.”

Their rivals have pounced on them for their seemingly soft stances. “You walk around and talk to voters, at least Republican voters, and it’s things like this that just drive them up a wall,” said Matt Wolfe, who is running as a Republican for an at-large seat. “You see Bobby Henon under federal indictment, still the majority leader of Council. No Democrats have called for his resignation or his removal as majority leader. No Republican has either. What’s wrong with this picture?”

Who are the challengers?

In addition to Wolfe, 63, a ward leader and lawyer from West Philadelphia, four other challengers are on the May 21 ballot. Four of the seven candidates are also from the Northeast. Four are ward leaders. There is one female challenger, Irina Goldstein; otherwise the slate is six men, five of them white.

“I was hoping for a little bit more dynamism, a little bit more alternative for voters that will reach beyond where the Philly GOP has been,” said Albert Eisenberg, a Republican political consultant who has worked for the city party.

“It’s terrible optics. This is an urban GOP, and you’re looking at the people and it’s not representative," Eisenberg said. He also said he hasn’t seen either incumbent use the "bully pulpit to further a conservative agenda that will appeal to Philadelphians.”

Dan Tinney is the best-funded challenger, and has high-profile endorsements from several labor unions, the Fraternal Order of Police, and White, the city’s lone Republican legislator in Harrisburg. Tinney, 37, also heads the 66th Ward, a GOP stronghold. He ran unsuccessfully in 2015 and has experience in business and organized labor, which he touts as a unique perspective.

Goldstein, 35, is an immigrant, with a background in the fashion industry, who hopes to stand out in a field of mostly older white men. “People hear my story, they say, ‘You’re an immigrant, you lived in refugee camps. Your whole story sounds like you should be a Democrat.’ Yeah, but they’re too far left,” said Goldstein, who switched her registration from Democratic to Republican last August. “The great thing about most people in Philadelphia is they are in the middle.” Goldstein has criticized Trump and ICE in Facebook posts, which she told The Inquirer were meant as satire.

Bill Heeney Sr., 60, who owns a courier business and lives in Torresdale, heads the 62nd Ward and is an outspoken critic of the incumbents. He’s also taken heat for a string of racist and misogynistic Facebook posts unearthed and published by the news site Billy Penn.

Drew Murray, the only candidate from Center City, became a Republican four months ago. Murray, 47, is the head of the Logan Square Neighborhood Association. “I’ve always been very middle of the road," Murray said. "When I was a Democrat, I described myself as a conservative Democrat. Now that I’m a Republican, I say I’m a moderate Republican.”