America is indeed a nation built by immigrants. But if you justify continuing massive immigration based on the history of immigration, you neglect that the situation that required massive immigration have ended.
Immigration made America the great country it is. We can take pride in accepting people from all around the world and making them Americans. We are a nation of ideas and not of blood and soil. So we can do that almost uniquely in the world.
Proponents of open borders will say that immigrants built America, admitting that America received a benefit from their hard work.
Just because an America in the past that was expanding across the continent to link the Atlantic and Pacific coasts needed every immigrant who could make it across the seas and swing a hammer does not mean that America continues to need the same level--or type--of immigration forever.
And controlling our borders to stop illegal immigration means that America can regulate the still-large number of legal immigrants to continue to benefit America under conditions that don't require as many unskilled people (percent and not sheer numbers) who in fact compete with those already here who would like to climb the economic ladder.
Limiting the number coming in also makes it more likely that immigrants will follow the path of assimilation that past ethnic groups have followed to achieve success in America.
Face it, the battle for open American borders is just away for progressives to signal their virtue, to bring in people they believe will vote for their side, and to make sure they have cheap labor to do their landscaping.
Remember, that big monument in New York City harbor is the Statue of Liberty and not the Statue of Unrestricted Immigration. Immigration should bolster our liberty and benefit America rather than a right that the rest of the world has granted to them.
I honestly don't understand how the Left can say people like me who believe anybody can be an American--if they accept our ideas that we based our country on--are racists. America will be America regardless of the race, religion, or ethnicity of our people as long as the people here assimilate and embrace the ideas of our country--as past immigrants who changed the demographics of America since 1776 did.
On this anniversary of our independence, let's try to remember the ideals of liberty that made us free and attracted the immigrants who made us a great and free nation.
And yeah, I've argued for this view of acceptance long before Trump was president.