Here is what President Trump has said about the need for US border protection and a wall, and this is relevant to Australians, wanting secure borders as well:
“THE PRESIDENT: My fellow Americans: Tonight, I am speaking to you because there is a growing humanitarian and security crisis at our southern border. Every day, Customs and Border Patrol agents encounter thousands of illegal immigrants trying to enter our country. We are out of space to hold them, and we have no way to promptly return them back home to their country. America proudly welcomes millions of lawful immigrants who enrich our society and contribute to our nation. But all Americans are hurt by uncontrolled, illegal migration. It strains public resources and drives down jobs and wages. Among those hardest hit are African Americans and Hispanic Americans. Our southern border is a pipeline for vast quantities of illegal drugs, including meth, heroin, cocaine, and fentanyl. Every week, 300 of our citizens are killed by heroin alone, 90 percent of which floods across from our southern border. More Americans will die from drugs this year than were killed in the entire Vietnam War. In the last two years, ICE officers made 266,000 arrests of aliens with criminal records, including those charged or convicted of 100,000 assaults, 30,000 sex crimes, and 4,000 violent killings. Over the years, thousands of Americans have been brutally killed by those who illegally entered our country, and thousands more lives will be lost if we don’t act right now.