While debate rages about the caravans of migrants coming from Central America and the response by President Trump's administration, what's been lost is that Trump has several additional options available for even more aggressive action to combat illegal immigration.

Starting with the highest profile move of all, Trump can move troops to the border. Thus far, the members of the military deployed to the border have played a supporting role to the Border Patrol by carrying out logistical tasks such as laying additional barbed wire and ferrying Border Patrol agents via military aircraft. However, the president could continue adding troops to the border and turn border security entirely over to the military. Defense of the nation’s borders is a matter of national security, not law enforcement. The Posse Comitatus Act (a federal statute prohibiting the use of military in civilian law enforcement) would not be triggered.

This approach could almost completely shut down illegal border crossings, if done with adequate manpower. In addition to curbing our nation’s illegal immigration crisis, this would also strike a blow to the illegal drug trade. For example, 80 percent of the finished fentanyl in our country comes across the U.S.-Mexico border near San Diego, Calif.

[Related: Trump: The border wall 'pays for itself' so 'get it done!']

Trump could also use his authority under section 212(f) of the Immigration and Nationality Act to stop the entry of all potential immigrants from the Central American nations from which the caravans originated, until such time as he decides that our immigration situation with those nations has returned to a safer state of affairs. Because the president’s authority under 212(f) is very broad, it can also be used to block the asylum seekers in the caravans (along with others from the same countries) until such time as the president is satisfied that any crisis and its causes have passed.

Additionally, using the same authority, the Trump administration could block the approximately 10,000 temporary work visas that are issued to citizens of those same nations every year. This hardball step would put even more pressure on the governments of Guatemala, El Salvador, and Honduras to stem the tide of their own citizens coming illegally to America’s borders.

Trump could also use his 212(f) authority to restrict Mexican citizens from taking advantage of temporary work visas in the same manner described for Central Americans. While there are only about 10,000 temporary work visas provided to citizens of the Central American nations, there are approximately 200,000 provided to Mexican citizens. If presented with backlash from U.S. businesses that depend on those workers, Trump could provide positive incentives for cooperation to the Mexican government. For example, if Mexico were to meet benchmarks to secure their southern border, thereby stemming some of the illegal immigration to America, the administration could offer to replace the work visas denied to the Central Americans with visas offered to Mexican citizens.

Finally, it should be noted that recent news reports indicate that Trump is actively pursuing a third-party agreement with Mexico to house illegals in Mexico until they are completely processed within our U.S. system, with those rejected being returned to their homeland without ever setting foot in our country. Such an agreement would provide the most diplomatic long-term solution available to the president as it puts us in a position of partnership with Mexico to stem the tide of illegal immigration coming across our Southern border even while the foundation is laid for stronger economic ties between our neighboring countries into the future.

The migrant caravan remains an ongoing threat to our country's sovereignty and safety. President Trump should carefully consider these more aggressive options and act as he and his advisers see fit.

Ken Cuccinelli (@KenCuccinelli) is the former Attorney General of Virginia.