DES MOINES — Ted Cruz's Iowa moment has arrived.

The U.S. senator from Texas, who has worked for months to manage expectations in the first early voting state, is starting to flirt with top-tier status as his campaign zeroes in on this critical presidential proving ground.

He has visited the state five times over the last six weeks. His paid staff in Iowa has quadrupled from what it was just two months ago. His campaign has launched its first major ad buy in Iowa, an initial six-digit purchase on TV and radio. And he's secured a big-name endorsement from U.S. Rep. Steve King of Iowa, with another social conservative kingmaker, Bob Vander Plaats, expected to line up behind him soon.

Whether Cruz likes it or not, expectations for his campaign in the state have risen accordingly.

“I’ll be honest — I think they’re as high as they’ve ever been and they’re only going to get higher," said Craig Robinson, a former state party official who writes the influential Iowa Republican blog.

The growing expectations could pose a new dynamic to Cruz and his aides, whom have long insisted they are running a national campaign that does not hinge on his performance in a single state. The candidate himself regularly brushes off questions about any state being a must-win, asserting his campaign is "all in" across the map, with the organization and resources to go the distance.

Keeping expectations in check could be an especially important task this cycle, which has already seen an early Iowa frontrunner — Wisconsin Gov. Scott Walker — slip from dominance there, only to drop out of the entire race several weeks later.Well aware of the booms and busts that have plagued other campaigns, Cruz's supporters in Iowa insist his rise is of a different variety.

"I believe the momentum is there just at the right time," said Steve Holt, an Iowa state representative. "This is not going to be a momentum like some have been — just up and down, and then it's gone."

“He’s slowly going up," said Omar Marquez, a junior at Briar Cliff University in Sioux City, where Cruz held a town hall Friday morning. "You see other candidates — they’re already at the top like [Donald] Trump. You expect them to fizzle out, but I think it’s better to start slower."

Cruz's slow-but-steady rise in Iowa has not been accidental. While other GOP candidates were competing for oxygen this summer with Walker and then Trump, Cruz's campaign was a little more focused on laying groundwork in states deeper into the primary calendar, such as the group of mostly southern states, including Texas, that are set to vote March 1 in what is being called the "SEC primary." As a result, Cruz's efforts in Iowa did not begin ramping up in earnest until Labor Day, two weeks after which he opened his first campaign office in the state.

"You know, Scripture talks about building your house on a foundation of rock and not on sand," Cruz said at the time. "This campaign is designed to be built on a foundation of rock."

Cruz's campaign has at least one county chair in all 99 counties of Iowa as well as congressional district coordinators covering the entire state. It has eight paid staffers — up from two in September and one over the summer, when state director Bryan English was working alone out of his living room. And Cruz himself is showing up in the state more often, having public events scheduled in the state during seven of the 11 weeks since Labor Day.

Cruz's campaign in Iowa received a big boost Monday when he won the support of King, an influential figure in conservative circles who could open doors for Cruz throughout the state. By the end of the week, Cruz had picked up the endorsement of Loras Schulte, who had to give up his membership on the Iowa GOP State Central Committee to back Cruz.

"It didn't hurt” when King endorsed Cruz, Schulte said. “When he announced on Monday, it was kind of a personal confirmation that, yes, I had made the right choice."

The candidate’s Iowa polling average, as calculated by the website RealClearPolitics, has increased more than 5 percentage points since Sept. 7, when he was bunched together with several other GOP candidates in the mid-single digits. Now Cruz and fellow U.S. Sen. Marco Rubio of Florida comprise a tier of their own behind frontrunners Ben Carson and Trump.

As he stumped across the state Friday, it was easy to see why Cruz's star has risen in Iowa. After a forum in Des Moines went way over its scheduled length — stretching on for more than three hours as several inches of snow blanketed the city — a still-lively Cruz was holding court in his reception room, taking another half hour of questions from a crowd spilling out into the hallways.

At standing-room-only town halls earlier Friday in Sioux City and Harlan, Cruz had King on hand as he shored up his credentials on the months-long hottest topic in the Republican race for the White House: immigration. While some GOP candidates were still finding their footing on the issue Friday, Cruz was already taking credit for weeks ago being the "lonely voice" against President Obama's plan to admit Syrian refugees to the United States.

"When I laid out this position several months ago, many in the media described it as somehow being out of the mainstream," Cruz told reporters after a town hall Friday afternoon in Harlan. "We now have roughly 30 governors who stepped forward and agreed with the position I was articulating two months ago."

To be sure, Cruz still has work to do in Iowa. With 30-some counties under his belt, he is far from fulfilling his promise to visit all 99 counties in the state, an endeavor that was not helped by a snow storm that caused him to cancel three stops on Saturday. Also on Cruz's to-do list is the completion of his 99 Iowa Pastors initiative, a key part of his outreach to the evangelical community that aims to designate a supportive faith leader in every county in the state.

Cruz's biggest challenge in Iowa, however, ranges beyond this state’s borders. That's his months-long inability to overcome the two other candidates vying for voters most fed up with Washington, D.C.: billionaire Trump and retired neurosurgeon Carson. Each is a high-risk target — Trump, because of his penchant for punching back, and Carson, because of his high favorability ratings.

"I think the biggest obstacle is how do you peel voters and still appeal to them?" Robinson said. "You have to peel votes away from Ben Carson, but to do it, you might have to get your hands a little dirty."

Cruz has shown no willingness to do that so far. While he distanced himself Friday from Trump's flirtation with a national registry for American Muslims, Cruz chastised reporters for the umpteenth time when they tried to coax a sharper contrast out of him.

"I'll tell you my policy views, but I have no interest in attacking Donald Trump or for that matter, attacking Ben Carson," Cruz said before a town hall in Sioux City.

Cruz is not the only ascendant GOP candidate in the Hawkeye State, where Rubio is also gaining traction following a series of strong debate performances. Another freshman senator who was elected with the backing of the Tea Party, Rubio was embarking on his longest trip to the state yet — five days — while Cruz was there Friday.

The rivalry between the two senators has intensified since the last Republican debate, when Cruz started sketching battle lines over Rubio's involvement in immigration reform efforts two years ago. In the wake of the recent Paris terrorist attacks, Rubio has waged his own offensive against Cruz, going after the Texan for voting to "weaken" national intelligence programs that could prevent a similar tragedy in America.

"If, God forbid, tomorrow morning there is a terrorist attack on the United States, the first question that we hope to answer to is, 'Why didn't you know about this, and why didn't you stop it?' And the answer better not be because a program" was not in place, Rubio said Saturday evening at a rally in West Des Moines. "There are even people in my party that know better than that."

At a town hall hours earlier in Cedar Rapids, Rubio was just as emphatic about national security, saying that under Obama, the country is "eviscerating our own capabilities to gather intelligence on these lunatics." After the event, Carl Hatcher of Cedar Rapids suggested the differences between the two senators are broader than one issue.

"I see Sen. Cruz as more of a hard-edged, legalistic type of a person, very dedicated to his principles but not able to work with other people," Hatcher said. "And I think Sen. Rubio, in his time in his Senate, he has reached out to others, so I think he's more of a consensus builder."

Cruz is set to return to Iowa after Thanksgiving, when he is scheduled to speak on Dec. 5 at FreedomWorks' Rising Tide Summit in Cedar Rapids. He was among the first several candidates to RSVP.