Donald Trump's win in Indiana yesterday should come as no surprise. He has figured out how to lead the Republican presidential race by tapping into what Republican voters want to hear. Unfortunately, what they want to hear, and what Trump has been advocating, would scale back civil liberties, impose protectionist laws, enact a bomb-friendly foreign policy and create barriers with other nations. But none of this stuff is new. In fact, everything Trump talks about mirrors attitudes and policies, if not tones, pushed by mainstream conservatives and Republicans for decades.

With that in mind, here are six ways Donald Trump's ideas originate from conservatives and the GOP:

1. That God Dang Wall

Long before Trump conceived of a plan to build a wall on the border with Mexico, Republican politicians from Sen. John McCain of Arizona to the former Massachusetts governor and 2012 Republican presidential nominee Mitt Romney were rallying the Republican base with promises of building some sort of barrier on the border. Further, with major Republican backing, Congress passed the Secure the Fence Act of 2006, which promised to build 700 miles of barrier along the border. They tried in 2009 and again in 2013 to get even more built. Too bad GOP politicians always forget that the majority of immigrants coming to America don't come across the border illegally but rather overstay their visas.

1. A Big Middle Finger to Immigrants

The way Donald Trump talks about immigrants seems scary. After all, he's said that "when Mexico sends its people, they're bringing drugs, they're bring crime, they're rapists." But his rhetoric is not that far off from conservative writers past and present at places like National Review. Reason's Nick Gillespie wrote:

According to National Review's Ramesh Ponnuru, "a hard line" on immigration is not simply one issue among many but is now a "defining" issue for contemporary conservatism. At least going back to the 1990s, the magazine, despite being edited by an immigrant (the Brit John O'Sullivan) inveighed against immigration in article after article.

1. Taking a Sht on Muslims

You've probably heard about Donald Trump's proposal to temporarily ban Muslims from entering the United States by now. Many writers and politicians have dismissed the idea, but when Rep. Peter King (R-N.Y.) told a radio station that the ban "goes beyond American values," his sincerity has to be taken with a grain of salt. Why? King may have not advocated for a ban on Muslims, but he has long advocated for heavy surveillance of their communities. After the terrorist attack in San Bernardino, Calif., King said at a press conference that the way to stop future attacks was to allow more profiling of Muslims.

1. Defense Spending (Peace Through Strength B.S.)

Trump tends to change his tune on defense spending depending on who he's talking to. But there is no doubt that he stole his peace through strength mantra from neoconservative talking points. Trump told a crowd at Liberty University recently that "we need to build our military, so big, so strong, so powerful that nobody, nobody is going to want to mess with us." The statement brought cheers from the crowd because neoconservatives from Weekly Standard editor Bill Kristol to former United Nations Ambassador John Bolton have been so successful at promoting among their base the idea that increases in defense spending lead to peace.

Chew on this though: Spending on homeland security and military grew by 90 percent in inflation-adjusted dollars since 2000, yet conservatives and Republicans still demand that the U.S. increase military spending even more.

1. Chinese Trade Protectionism

Labeling a country a currency manipulator and sparking a potential trade war may be a dumb idea for a presidential candidate, but Donald Trump has made that act central to his campaign. That even sparked criticism from former Republican Presidential nominee Mitt Romney. Politico reported in March:

Romney's speech Thursday in Utah took aim at a few different components of Trump's agenda. "His proposed 35% tariff-like penalties would instigate a trade war that would raise prices for consumers, kill export jobs, and lead entrepreneurs and businesses to flee America," Romney declared.

Too bad Romney advocated for something very close to what Trump is proposing back when he ran in 2012. From Politico:

But back in the 2012 campaign, Romney offered a similar threat to China: "On day one, I will label China a currency manipulator, which will allow me as president to be able to put in place, if necessary, tariffs where I believe that they are taking unfair advantage of our manufacturers."

1. This one is a secret. But once you find out, you won't be surprised.

Correction: In the section on Muslims, video appears of a man who is not Muslim, but Sikh. We apologize for the error.