Editor's note: Julian E. Zelizer is a professor of history and public affairs at Princeton University. He is the author of "Arsenal of Democracy " and a book on former President Carter to be published next fall by Times Books. He is also the editor of a new book about former President George W. Bush to be published next fall by Princeton University Press.

(CNN) -- During a speech at an event called "Freedom Fest," former Alaska Gov. Sarah Palin warned Tea Party activists that while government spending was a bad thing, conservatives should not go too far and start calling for reductions in the military budget.

While Palin told the crowd in Norfolk, Virginia, "Something has to be done urgently to stop the out-of-control Obama-Reid-Pelosi spending machine," she also told them, "We must make sure, however, that we do nothing to undermine the effectiveness of our military."

Palin's speech touched on a historic problem for the conservative movement. Ever since conservatives embraced a hawkish stance toward national security policy in the early Cold War in the late 1940s and started to challenge Democrats for not being tough enough, national security has always been the poison pill for anti-government conservatism.

Despite all their rhetoric about the dangers of government intervention and the virtues of private markets, conservatives have rather consistently supported an expansion of the government when it comes to national security.

There was a time when there were prominent conservative voices that were more skeptical. Ohio Sen. Robert Taft, "Mr. Republican," tried to prevent the expansion of the national security state after World War II. Taft opposed President Truman as Truman pushed to grow the government in the fight against communism. Taft warned that total security was impossible and that if Americans created a garrison state to fight communism, politicians would destroy the "America we are trying to preserve."

But Taft's arguments were drowned out by a more hawkish Republican outlook. The intellectual William Buckley, who founded the National Review in 1955, argued that conservatives had to "accept Big Government for the duration -- for neither an offensive nor a defensive war can be waged ... except through the instrument of a totalitarian bureaucracy within our shores."

Buckley wrote that Republicans "will have to support large armies and air forces, atomic energy, central intelligence, war production boards, and the attendant centralization of power in Washington -- even with Truman at the reins of it all." Buckley's National Review became a central outlet for such opinions. In response to libertarian critics, Buckley explained, "National security is a proper concern for the libertarian because without it he stands to lose -- in this case -- all his freedom."

Since the 1950s, Republicans have embraced Buckley's arguments, and the party has championed a strong and expansive national security state. During the 1980s, President Reagan followed Buckley's approach.

On the one hand, Reagan railed against Washington when it came to domestic problems, saying, "Government is not the solution to our problem, government is our problem." Yet when it came to national security, he acted and sounded very different. Working with Secretary of Defense Caspar Weinberger, Reagan pushed for huge increases in defense spending. In March 1981, Reagan proposed the largest military budget since World War II, and for the next four years, defense spending would constitute 30 percent of the federal budget.

Colin Powell -- the senior military assistant to Weinberger, whose nickname was Cap -- later wrote, "The once-feared Cap the Knife had become, to his critics, Cap the Ladle." Reagan reversed the trend of declining military spending that Congress had undertaken since 1968. Reagan was confident that Americans agreed with this approach: "When I was asked during the campaign about what I would do if it came down to a choice between defense and deficits, I always said national security would come first, and the people applauded every time."

In truth, once conservatives were in power they also started to expand a good deal of domestic spending as well, sometimes learning to live with the continued power of Democrats on Capitol Hill and other times realizing that constituents, including conservatives, often wanted the very government services that Republicans derided.

While Reagan was president the federal budget continued to grow, Social Security and Medicare were protected -- after Reagan backed off an early effort to cut benefits -- and the number of civil servants increased.

While Republicans were often reluctant in their acceptance of domestic spending, they continued to enthusiastically champion government when it came to national security. This was where, to the GOP, government was the answer.

Following 9/11, President George W. Bush relied on government as the solution to the nation's problems. In addition to significant increases in defense spending, Bush authorized a massive expansion of executive power in order to provide the federal government more power to fight against terrorist networks. The Patriot Act (2001), for example, vastly enhanced the authority of the government to use wiretaps, to search the material of third parties that possessed records pertaining to suspected terrorists, and to close down fundraising organizations connected with terrorism.

As in Reagan's presidency, other forms of spending increased as well. Bush famously passed the largest expansion of Medicare by adding a prescription drug benefit, and Republicans passed a big agricultural subsidy measure. When financial markets crashed in the fall of 2008, Bush secured a huge federal bailout of Wall Street to create a modicum of economic stability.

Importantly, Democrats have their own inconsistencies. While the Democratic Party has generally supported using the federal government to deal with economic and social problems, many Democrats have expressed deep distrust of federal officials when it comes to national security. They have warned that government and military officials act based on their own agenda or in response to the needs of a defense establishment.

But when it comes to Republicans, Palin's recent comments at the conservative rally show why voters should take right-wing arguments about the dangers of government with a grain of salt. While conservative activists like to talk about a choice between big government and small government, the real debate is over what kinds of government we must have, what our priorities should be, and where our federal money should be directed.

The opinions expressed in this commentary are solely those of Julian E. Zelizer.