With all the events occurring along the United States-Mexico border, one thing is certain- the border must be secured. And not only just America's southern border, but all of its borders.
The U.S.-Mexico is not only being overrun with minors, but all sorts of illegal immigrants, not to mention drug runners and terrorists (e.g. Hezbollah). In fact, many terrorists from Muslim countries have learned to speak Spanish and hence would try to pass themselves off as Mexicans or Central America. Meanwhile, tunnels being used for drug trafficking have been discovered underneath the border.
Next, there is the U.S.-Canada border, which can be divided into two borders: the northern border (between Canada and the Lower 48- 3,987 miles) and the Alaska-Canada border (1,538 miles). Given the former's vast size, it would no doubt be tempting for someone to try and sneak across. Tunnels used for drug trafficking have been discovered along this border as well. As for the border between Alaska and Canada, it seems a less likely scenario (given the terrain and climate). However, there might be those willing to brave the elements. In fact, Alaska's border with British Columbia would be a more likely scenario than the border between Alaska and the Yukon Territory.
Then there is Hawaii and America's overseas territories (e.g. Puerto Rico, Guam). Although even less likely destinations for illegal immigrants (considering they are islands) there is still a slim chance someone could sneak onto any of them, then head for the mainland (although the journey to the mainland might be more problematic due to identification being required, unless someone agrees to smuggle them in).
Finally, there are America's ports of journey. They are already destinations for smugglers, so who is to say they wouldn't be destinations for illegal immigrants?
Needless to say, the borders must be secured. And that can be accomplished by completing the fence along the southern border, as well as increased security and cooperation between America and its neighbors. Doing so will make America a safer place to live.