Nine months after first introducing a controversial travel ban that filled airports with protesters, the White House is considering implementing a new and more targeted ban to get stricter on incoming immigration.

The measure is the latest in the contentious efforts by Donald Trump to make good on a central campaign promise — to strengthen the US border, and to make sure that foreign nationals who want to come to America to hurt the country are not able to do so.

Here’s what you need to know about the new measures.

Who is developing the latest proposal?

Mr Trump is considering recommendations from the Department of Homeland Security on th new rules. Acting Homeland Security Secretary Elaine Duke is the face of that effort, and submitted a new report to the President last week That report details potential new travel restrictions that could be put in place.

Are new countries going to be added to the travel ban?

At this point, it is not clear what countries might be added, or taken off, of the targets list. The White House has so far refused to disclose those names, and how many countries might be on the list in general.

New York City bodegas strike to protest Trump's travel ban Show all 27 1 /27 New York City bodegas strike to protest Trump's travel ban New York City bodegas strike to protest Trump's travel ban Ethnic Yemenis and supporters protest against President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban Men pray during a protest by ethnic Yemenis and supporters over President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban Ethnic Yemenis and supporters protest against President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban Men pray during a protest by ethnic Yemenis and supporters over President Donald Trump's executive order temporarily banning immigrants and refugees from seven Muslim-majority countries, including Yemen on February 2, 2017 in the Brooklyn borough of New York City. At least 1,000 Yemeni-owned bodegas and grocery-stores across the city shut down from noon to 8 p.m. today to protest the order. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People gather for evening prayer at a rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally with flags at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest US President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban People rally at Brooklyn Borough Hall as Yemeni bodega and grocery-stores shut down to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen, on February 2, 2017 in New York. Bryan R. Smith/AFP/Getty New York City bodegas strike to protest Trump's travel ban A Yemeni business owner places a sign on the gate of his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban A Yemeni business owner places a sign on the gate of his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban NEW YORK, NY - FEBRUARY 02: Yemeni business owner Musa closes the gate to his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty New York City bodegas strike to protest Trump's travel ban A Yemeni business owner closes the gate to his store February 2, 2017 in the Brooklyn borough of New York City. Across the city, Yemeni owned bodega and grocery-stores will shut down from noon to 8 p.m. to protest President Donald Trump's Executive Order banning immigrants and refugees from seven Muslim-majority countries, including Yemen. It is expected that over 1000 stores will be closed in protest with workers and owners participating in an afternoon rally in Brooklyn. Spencer Platt/Getty

But, they have outlined their basic considerations. Basically, after the agency raised the baseline for vetting standards for people coming from other countries, and countries that don’t meet that threshold may see enhanced measures.

A report from the Wall Street Journal, citing unnamed sources, indicates that the Department of Homeland Security has identified 17 countries that were not meeting vetting standards.

What kinds of measures are these countries facing?

Again, exacting details are hazy at this point. But, the administration appears poised to impose a variety of stricter procedures for individuals travelling from certain countries. That could include enhanced vetting procedures, or harsher restrictions on travel.

What’s wrong with the old travel ban?

Mr Trump’s travel ban — which was the second attempt to implement such a measure — was not cleared by the courts to go into effect until June, and it was only written to be implemented for a temporary period. The order suspended the US refugee program for 120 days and limited travel from six predominantly Muslim countries for 90 days.

As such, the “problem” — in the strictly non-political sense — is that the 90 days are up Sunday.

Why were the first travel bans so controversial?

For opponents of Mr Trump, and for those who have philosophical differences with the President when it comes to America’s relationship with immigration, the measures were outrageous because they appeared to target people based upon their religion, not on the basis of risk analysis. In addition to that, opponents pointed out that the US has fairly strict vetting programmes for refugees at the moment.