To terrorists, travel documents are weapons. Family-based immigration visas, fiancé visas, and other documents required for entry into our nation can be used as the Trojan horses, the means to destructive plots.

Such was the case with a Pakistani visa applicant who entered the United States in 2014 when her soon-to-be husband submitted a petition to the Department of Homeland Security. U.S. officials requested more evidence to verify that she and her future husband had actually met in person — a requirement for fiancé visas — but the evidence was never provided.

The petition was incomplete. Yet, she was approved for a visa and allowed entry into the United States.

Americans came to know her as Tashfeen Malik in December 2015. She and her husband opened fire at a holiday party at the San Bernardino Inland Regional Center, killing 14 Americans and injuring 22 others. The current visa vetting system allowed Malik to get through.

But it’s not just Tashfeen Malik who wishes us harm. And the negligence may have not been a fluke.

Earlier this year, the DHS Inspector General stated in testimony that, “the present system presents risks to our national security — in that we may be admitting individuals who wish to do us harm, or who do not meet the requirements for a visa.”

The problem has existed for quite some time. Four years ago, a separate DHS Inspector General report revealed that some U.S. Citizenship and Immigration Services adjudicators were “required to approve specific cases against their will,” giving visas a rubber stamp even when fraud was suspected.

The report exposed that “getting to yes” was an unofficial policy of United States Citizenship and Immigration Services.

Those who want to do us harm can apply for visas and attempt to exploit the vulnerabilities in our vetting practices. Citizens bear the consequence of negligence in the system.

America is only as strong as our weakest link. Terrorists will always find a way to exploit the vulnerabilities in our immigration system to gain access to American soil, but we shouldn’t be able to look inside the immigration files of an individual and see gaping holes. Our top priority must always be the safety and security of American citizens.

We should require immigration officials to use available tools to determine who may be a threat to the United States. Social media is a hotbed for jihadi propaganda. Immigration officials should be required to look at all publically available information — like Facebook profiles and Twitter accounts — of visa applicants to learn more about individuals who are trying to gain access to our country.

Even employers do social media checks on potential employees. It only makes sense for our government to do the same when it comes to potential visa holders.

We should have heightened scrutiny for visa applications coming from countries where we have heightened security concerns. This includes countries like Iran, Iraq, Libya, Somalia, Syria, Sudan, Yemen, and any other countries where the Secretary of State determines extra scrutiny is warranted.

We should require in-person interviews with those seeking immigration benefits in the U.S. We need to talk to the individuals who want to change their immigration status. Do their stories check out? What is their motive for staying here? We need to know.

We should make sure we are using the most innovative technology to detect fraud. We have cutting-edge, savvy, advanced analytics software solutions available. Immigration officials should have the most advanced software to safeguard against applications from individuals who pose a threat to our national security.

We should require that all requests for document translations and additional information on an applicant be completed; otherwise the application will automatically be denied. It’s just common sense.

Our commitment to visa security is a direct reflection of our commitment to the American people and the supreme law of the land. Entry into this country is a privilege, not a right. America’s No. 1 priority must be the safety and security of U.S. citizens. Period.

We cannot guarantee that terrorists will not attack again. But we must do everything in our power to remove the visa weapon from their arsenal.

Congressman J. Randy Forbes represents Virginia’s Fourth District, which includes Suffolk, in the U.S. House of Representatives. Visit his website at forbes.house.gov.