To that end, Mr. Thompson said the next president should have the courage to talk straight with the American people and bluntly say that Americans will have to confront both the soaring cost of entitlements and the need to remain committed in the war on terror, even when Iraq is "in the rear-view mirror." "This is a battle between the forces of civilization and of evil," he said, noting that reports over the weekend of a foiled plot against John F. Kennedy Airport in New York was proof positive that terrorism remains a real threat. "I listen to the Democratic congressional leaders and I hear them talking about how many [House and Senate] seats they're going to pick up because of this war," he said. "I listened to one of their presidential candidates talk about that this is a phony war, the war on terror. This is what passes for policy today in the Democratic Party."

Mr. Thompson also zinged Democrats for proposing a budget that boosts spending dramatically while remaining silent on the extension of investment-focused tax cuts that expire in 2010. "The Democrats are hot after repealing all of that, the engine that's driving this economy."

On judicial nominations, Mr. Thompson recalled his role in helping guide John Roberts through the confirmation process. He said nominees like Chief Justice Roberts are necessary because too many judges were "waking up in the morning and deciding what social policy should be." He warned federal judges: "If they continue to act like politicians, the American people are going to start treating them like politicians, and that's not good news for them."

But Mr. Thompson's biggest response came when he addressed immigration. "We are a nation of compassion, a nation of immigrants," he told the crowd. "But this is our home, and whether you're a first-generation American, a third-generation American or a brand newly minted American, this is our home and we get to decide who comes into our home." At that, much of the crowd rose and applauded midspeech.

While it was clear Mr. Thompson has found a way to excite the Republican base, his impending candidacy is at a crossroads. He has run what Fred Barnes of The Weekly Standard calls "the greatest non-campaign campaign I've ever seen" and has managed to land in the upper ranks of the crowded GOP field without spending any money. But when his actual campaign begins next month, a different standard of success will be applied.