Newt Gingrich delivered a closing argument to Iowa Republicans this week, saying that he is the most effective conservative in the race for the GOP presidential nomination even as his opponents continued hammering him with negative ads.

In speeches at a shopping mall, a chocolate shop, pizza joints and a series of telephone town halls with thousands of Iowans listening in, Gingrich made the case that he has been the change agent and champion of conservatism his entire political career.

“We’ve had this long drama in the Republican Party going back to Goldwater and Reagan and Kemp and then me,” Gingrich said. “There really are two wings of the Republican Party, and they really think very differently.”

Gingrich said that he has always stood with the conservative wing and that Mitt Romney, a former Massachusetts governor, represents the “timid,” “moderate,” “conciliatory” wing.

The former House speaker acknowledged that it remains unclear whether he can survive the barrage of TV ads coming from rivals Rick Perry, governor of Texas, and Ron Paul, a Texas congressman, as well as an independent super PAC supporting Romney.

But in an interview with The Washington Post on his campaign bus as it rumbled across central Iowa, Gingrich said he remains better positioned than he expected to be at this point in the cycle after a bumpy year that included a near-collapse of his campaign in June and a slow crawl back to the top of the field.

Gingrich said his plan is to survive Iowa, perform respectably in New Hampshire and make it to South Carolina and Florida — the next two primary contests on the calendar. In those states, he said, he is well-positioned to contrast his conservatism with what he called Romney’s moderation.

Gingrich showcased that conservatism on the campaign trail this week, trotting out a series of fiscal conservatives who are supporting him, including economist Art Laffer and Michael Reagan, the son of the president who championed the low-tax, small-government theory of supply-side economics. His goal was not only to show that he has advocated for conservative principles throughout his political career, but also to draw a stark contrast with Romney, his leading competitor.

Gingrich described Romney as a “Massachusetts moderate who is timid about beating Obama, has a very weak economic plan, continues to defend mandates, raised taxes on businesses and appointed liberal judges because he’s a manager, not a change agent.” In contrast, he characterized himself as a “Reagan-Kemp supply-side conservative who for over 30 years has represented economic growth, dramatic change and a willingness to really take on the Washington establishment.”

Gingrich added that he almost understands what he described as the Washington establishment’s “antipathy” to his candidacy. “The level of change I represent is unacceptable to them,” he said.

That sentiment was echoed in a new ad that an independent super PAC working on Gingrich’s behalf, Winning Our Future, began airing in Iowa this week. In the ad, a narrator exhorts Republican caucusgoers: “Don’t let the liberal Republican establishment pick our candidate.”

Gingrich’s campaign also began running ads across Iowa in earnest this week, investing another $500,000 and reporting that he had raised $9 million so far this quarter — a dramatic improvement over the previous reporting period, in which he raised about $1 million and reported that much in debt. However, much of that $9 million came in the form of small-dollar donations and was raised through direct-mail solicitations — a costly fundraising strategy. As a result, it was unclear how much the campaign had to spend to raise the $9 million.

“We don’t know yet,” Gingrich said. “I have to come out strong enough to go to New Hampshire.”

Meanwhile, a senior Gingrich strategist, Kevin Kellems, cautioned voters and the media not to overstate the impression that Romney is surging toward victory. In an internal memo obtained by The Post, Kellems wrote: “Governor Romney remains stuck at the same levels he’s been at for five years — even after tens of millions in direct expenditures, hiring half of Washington and raising enormous sums for super PAC attacks. Imagine what Governor Romney’s numbers would look like now if anything sizable had been aimed at him? He would crumble, which obviously is not what Republicans are looking for when choosing a nominee to take on Barack Obama.”

In contrast, Kellems wrote of Gingrich: “Newt can outlast the rest of the field and emerge as the conservative alternative to Romney. Newt can take a punch and keep making the conservative case. Of course, the other huge advantage is Newt’s policy supremacy on job creation and economic growth — a substantive contrast that is resonating with voters and will continue to pay compound interest as we move through Iowa and New Hampshire to South Carolina and Florida.”