President Donald Trump made his first visit to California today, the first time he has done so since taking office last year. But even before his arrival, California's Democratic Governor Jerry Brown sent the President a fiery letter via Twitter, in which he counters Trump's vision of a walled U.S.-Mexican border with the idea of "focusing on bridges, not walls."

California is the nation's most populous state and is the world's sixth-largest economic entity, itself taking in $1.4 trillion in tax revenue in 2016.

As Brown lays out in his letter to Trump, "the sixth largest economy in the world is thriving. California has added almost 3 million jobs since the [economic] recovery began. But our prosperity is not built on isolation. Quite the opposite. California thrives because we welcome immigrants and innovators from across the globe."

More than 10.5 million immigrants make their home in California, making up 27 percent of the Golden State's total population. Over two million residents are either immigrant entrepreneurs or work for immigrant-owned companies. This gives immigrants an impressive share of California's economy.

"Such businesses also generated more than $775 billion in annual business revenue that year. In California, like the country as a whole, immigrants are currently punching far above their weight class as entrepreneurs, Such businesses also generated more than $775 billion in annual business revenue that year. In California, like the country as a whole, immigrants are currently punching far above their weight class as entrepreneurs," states New American Economy. Immigrants in California "contributed more than $117 billion in state and local taxes, as well as almost $262 billion in federal taxes."

The first purpose of Trump's tour, which kicked off this afternoon in San Diego, is to inspect designs for his proposed border wall with Mexico. Trump regularly touts the racist and easily falsifiable claims that undocumented immigrants pose a danger to our country.

But of course, while on the tour, Trump couldn't help but get a crack in at the Governor.

To which Governor Brown responded:

This all happens against the backdrop of tensions regarding immigration in the state, the same day spokesman for California's Immigration & Customs Enforcement agency resigned, after growing tired of Trump and Attorney General Jeff Sessions ongoing falsehoods about arrest rates and raids.

Last week, Sessions gave a speech to a hotel ballroom packed with 200 law enforcement officials in which he viciously reprimanded California for its refusal to enforce some federal immigration laws, which the state views as discriminatory and harmful. During the speech, Brown accused Trump and Sessions of “basically going to war against the state of California.” Sessions and the Department of Justice are suing California over so-called, albeit controversial, "sanctuary cities," where undocumented immigrants can live without the fear of deportation by the state.