WASHINGTON (Reuters) - President-elect Donald Trump has outlined a ten-point plan on his transition website for dealing with illegal immigration. Here is a look at what it would take to accomplish each of the ten goals. BUILD A WALL ON THE SOUTHERN BORDER: Trump has the legal authorization to build fences under the “Secure Fence Act” passed in 2006, but Congress would have to approve considerably more funding to wall off the entire southern border, which spans nearly 2,000 miles. There are also logistical challenges. Some areas of the border are privately owned, and the geography of some stretches would make construction extremely difficult. Trump previously said he would make Mexico pay for the wall, but that policy is not included on his post-election web site.   END CATCH-AND-RELEASE: To end the practice known as “catch and release,” under which immigrants are released pending court hearings, Trump could unilaterally shift policies, but full implementation would require significantly more detention space to hold migrants before they can see a judge. There is currently a 500,000-case backlog in U.S. immigration courts and recent court decisions prohibit him from detaining children with their parents for longer than 20 days.  ZERO TOLERANCE FOR CRIMINAL ALIENS: The Obama administration currently prioritizes immigrants convicted of serious crimes for deportation. But Trump could try to expand the definition of who is classified as a criminal alien or attempt to speed up removals of people who have been ordered deported. In any case, more funding for courts and personnel involved in apprehensions would likely be necessary.  BLOCKING FUNDING FOR SANCTUARY CITIES: Trump has threatened to cut off funding for so-called sanctuary cities such as Chicago and Los Angeles, where local law enforcement refuse to report undocumented immigrants they encounter to federal authorities. While Trump has the authority to cut some kinds of funding to the cities, mayors of those cities have said they will not be pressured to report migrants to federal agents.  CANCEL UNCONSTITUTIONAL EXECUTIVE ORDERS AND ENFORCE ALL IMMIGRATION LAWS: Trump has the authority to undo executive orders like DACA, which has provided temporary relief from deportation to more than 700,000 immigrants brought to the United States illegally as children. Enforcing all immigration laws would require Trump to deport an estimated 11 million immigrants living illegally in the United States. That would require large increases in funding from Congress to grow the current workforce of immigration agents and judges to be able to lawfully handle 11 million deportations. Locating so many immigrants, many in the country for years with deep family ties, would be logistically challenging and could spark public backlash.  SUSPEND THE ISSUANCE OF VISAS TO ANY PLACE WHERE ADEQUATE SCREENING CANNOT OCCUR: Similar to the “Muslim ban” Trump proposed during his campaign, this policy would be aimed at visa seekers from war-torn countries such as Syria and Iraq where many refugees and asylum seekers have sought to escape. Under current law, Trump could unilaterally suspend visas for any individuals or groups or people deemed “detrimental to the interests of the United States.”  The policy could face challenges in court, however, if it appears to discriminate against any one religion. ENSURE THAT OTHER COUNTRIES TAKE THEIR PEOPLE BACK WHEN WE ORDER THEM DEPORTED: The Obama administration has wrestled with the issue of forcing recalcitrant countries to take back people the United States is seeking to deport. Trump could ramp up diplomatic pressure on countries such as China, the country that has refused to repatriate the largest number of people ordered deported from the United States, but that could have wider diplomatic ramifications. FINALLY COMPLETE THE BIOMETRIC ENTRY-EXIT VISA TRACKING SYSTEM: Although mandated by law since Bill Clinton was president, the United States has yet to develop a system to track foreign visitors and determine if they leave the country when their visas expire. Getting a program up and running would require significant funding to collect and store biometric data such as fingerprints for every visa holder who enters and leaves the United States, and some experts have said the system is not practical.  TURN OFF THE JOBS AND BENEFITS MAGNET: Trump would need congressional approval to mandate a national database known as E-Verify that allows employers to check the immigration status of potential hires. Until such a system is in place, it is difficult to penalize employers who unknowingly hire undocumented immigrants using fake social security numbers.   REFORM LEGAL IMMIGRATION TO SERVE THE BEST INTERESTS OF AMERICA AND ITS WORKERS: The Department of Labor, the Department of Homeland Security and the Justice Department could  increase investigations of employers suspected of abusing visa programs such as H-1B that allow companies to hire foreign workers, often for a lower cost than what they would pay Americans. But Trump could face backlash from industries that rely on the program, including the technology sector, if he goes too far in revoking visas.  