This summer, we have all witnessed the heavy hand of government intervening in the freedom of speech, as the behavior of the Secret Service at both the Republican convention in Cleveland and the Democratic convention in Philadelphia was troubling and unconstitutional.

Though the First Amendment was originally written only to restrain Congress ("Congress shall make no law ... abridging the freedom of speech"), it is now uniformly interpreted to restrict all government in America from abridging the freedom of speech.

The reason this freedom is referred to as "the" freedom of speech is to reflect the belief of the Framers that the right to speak freely is pre-political. Stated differently, the freedom of speech is an integral aspect of our humanity. The government does not grant the freedom of speech; it is prohibited from interfering with it.

This is known as a negative right, in the sense that government is negated from interfering with a personal natural right. A natural right is one whose exercise does not require a government permission slip. Speech is the classic example.

The government removal of the press by command of the Republicans and the government removal of Sanders placards by command of the Democrats constitute not only an unheard-of commandeering of the government's coercive powers for a private purpose but also the government's abridging the freedom of speech.

The reasons for this are numerous, and not the least of them are our natural inclinations to think as we wish and to say what we think in pursuit of happiness and personal fulfillment. The practical reasons for this right are the needs of an informed electorate to challenge the government and demand transparency and accountability.

How did this play out during the hot weeks in Cleveland and Philadelphia? Not well.

Though the political parties are private entities with their own rules, they have invited their members and supporters to these quadrennial conventions for the purpose of engaging in public political conversations.

Yet if the Republicans wanted only pro-Trump sentiments to be expressed in the hall in Cleveland and if the Democrats wanted only pro-Clinton sentiments to be expressed in the hall in Philadelphia, since neither entity is the government, both are free to abridge the freedom of speech without legal consequences.

The consequences of such abridgments would presumably be political; those whose speech is silenced and those who oppose silencing public political speech would cast their votes against the silencers.

Yet this summer, the heavy hand of government was involved in silencing speech.

Here is the back story.

Because both Donald Trump and Hillary Clinton are entitled to Secret Service protection by virtue of a federal statute, the Secret Service either offered or demanded that it be the lead law enforcement agency providing general security -- not just to Trump and Clinton but for everyone -- at the conventions. In both cities, local officials went along with this.

The freedom of speech issues arose when the leadership of both conventions got so cozy with the Secret Service that they began using the federal agency as if it were private security, and they did so in such a manner as to preclude judicial intervention in aid of the freedom of speech.

Thus, when the Republican leadership wanted to quell a "Never Trump" boomlet on the convention floor, it had the Secret Service remove all reporters and producers -- including some of my Fox News colleagues -- from the floor. And when the Democratic leadership wanted to silence a pro-Bernie Sanders onslaught on the convention floor, it had the Secret Service confiscate Sanders placards from delegates on the floor.

The government removal of the press by command of the Republicans and the government removal of Sanders placards by command of the Democrats constitute not only an unheard-of commandeering of the government's coercive powers for a private purpose but also the government's abridging the freedom of speech. And all this was done quickly and without notice -- and without an opportunity for redress to the courts.

The first duty of government is to preserve life, liberty and property. It is a strange and dangerous government that stifles freedom for some fleeting private purpose. It is equally strange that a freedom-loving people would tolerate this.

The whole purpose of the First Amendment and its underlying values is to encourage open, wide, robust, unbridled debate about the policies and the personnel of the government. The prevailing judicial interpretations of these values quite properly keep the government out of the business of assessing the value and propriety of public political speech.

The First Amendment demands that the test for acceptance or rejection of speech in the marketplace of ideas be made by individuals -- uninfluenced, undeterred and unmolested by the government.

When the government stifles free choice in an area such as speech, it is no longer the people's servant. It has become their master. Do you know anyone outside the government who wants that?

Andrew P. Napolitano, a former judge of the Superior Court of New Jersey, is the senior judicial analyst at Fox News Channel.