Secretary of Defense James Mattis stepped down on Thursday, notifying President Trump in a letter that he believes someone should be in the role whose "views are better aligned with yours" when it comes to international alliances and partnerships.

Mattis submitted the letter one day after Trump announced the Islamic State has been defeated and he wants to pull all U.S. troops from Syria, much to the delight of Russia. In his letter, Mattis said one "core belief" he's always held is "that our strength as a nation is inextricably linked to the strength of our unique and comprehensive system of alliances and partnerships. While the U.S. remains the indispensable nation in the free world, we cannot protect our interests or serve that role effectively without maintaining strong alliances and showing respect to those allies."

He also believes the United States "must be resolute and unambiguous in our approach to those countries whose strategic interests are increasingly in tension with ours. It is clear that China and Russia, for example, want to shape a world consistent with their authoritarian model — gaining veto authority over other nations' economic, diplomatic, and security decisions — to promote their own interests at the expense of their neighbors, America, and our allies."

Allies must be treated with respect and the U.S. "must do everything possible to advance an international order that is most conducive to our security, prosperity, and values," Mattis continued, and because he is of the opinion that Trump has "the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position." His final day will be Feb. 28, 2019. Read the entire letter below. Catherine Garcia

White House senior adviser Stephen Miller appeared on Fox News Sunday to defend President Trump's Friday declaration of a national emergency to obtain funding for border wall construction — and host Chris Wallace did not let him off lightly.

"The president talks about an 'invasion' — he used that word multiple times on Friday — an 'invasion' on the southern border," Wallace said. "But let's look at the facts," he continued, citing statistics to show illegal border crossings have fallen dramatically in the last two decades; that the vast majority of heroin and fentanyl seizures at the border take place at official entry points, not unfenced areas; and that visa overstays now account for twice as many illegal entries to the United States as illicit border crossings.

"Again," Wallace concluded, "where's the national emergency to build a wall?"

After promising to address every fact Wallace raised, Miller responded by arguing that would-be illegal immigrants are now sneakier and more difficult to deport than they were two decades ago and that more drugs are not captured in unfenced areas of the border because there is not enough manpower there to capture them.

Wallace didn't seem convinced, but turned the conversation to constitutional questions concerning the national emergency, repeatedly pressing Miller on whether he can "name one case where a president has asked Congress for money, Congress has refused, and the president has then evoked national policy to get the money anyway?"

Miller refused to give Wallace the yes or no answer he sought, instead arguing the National Emergencies Act is Congress "saying the president could have this authority," so any time the president declares an emergency he automatically has congressional approval to spend money on the situation as he pleases.

Watch the full interview below, or read the transcript here. Bonnie Kristian

Heather Nauert, Trump's pick to replace Nikki Haley as U.S. ambassador to the United Nations, withdrew her name from consideration Saturday.

The State Department spokeswoman and former Fox News anchor said that it was in the best interest of her family that she remove her name from the process. "I am grateful to to President Trump and Secretary [Mike] Pompeo for the trust they placed in me," Nauert said in a statement. "However, the past two months have been grueling for my family and therefore it is in the best interest of my family that I withdraw my name from consideration."

Pompeo addressed Nauert's decision, praising her job performance at the State Department and wishing her "nothing but the best."

The Washington Post reported Nauert's nomination faced complications and that her security investigation was delayed because 10 years ago she hired a foreign-born nanny who did not have a proper work visa. Additionally, the report says Nauert did not pay her taxes on the hire at the proper time.

The State Department said Trump will select a new nominee soon. Tim O'Donnell

Police in Chicago on Saturday said their investigation of the alleged assault against Empire actor Jussie Smollett has changed focus following the interview of two brothers linked to the case.

"We can confirm that the information received from the individuals questioned by police earlier in the Empire case has in fact shifted the trajectory of the investigation," said a police statement. "We've reached out to the Empire cast member's attorney to request a follow-up interview."

An unnamed police source told NBC the new information suggests Smollett hired two men to stage the attack. Smollett's lawyers vehemently denied that report, saying, "Nothing is further from the truth and anyone claiming otherwise is lying."

Smollett has likewise expressed indignation at accusations that his account is not accurate. "It's not necessarily that you don't believe that this is the truth," he said Thursday. "You don't even want to see the truth."

Like his Empire character, Smollett is gay. He alleged two people yelled racist and homophobic slurs at him, beat him, poured a substance that may have been bleach on his body, and put a noose around his neck as he left a Chicago restaurant. The two brothers who spoke with police were arrested and at first considered suspects, but they have since been released without charges and are no longer suspected. One of the brothers is Smollett's personal trainer, his attorneys said. Bonnie Kristian

The man who fatally shot five people and wounded six more in Aurora, Illinois, on Friday was armed with a handgun he should not have been able to purchase, local authorities have revealed.

The shooter, identified as Gary Martin, had been arrested in Aurora six times for "traffic and domestic battery-related issues," said Aurora Police Chief Kristen Ziman, and he was convicted of aggravated assault in Mississippi in 1995. That felony conviction should have been detected by the background check Martin underwent to purchase his gun. It was not.

Though a second background check for Martin's concealed carry permit application did alert to his record, he already had the weapon in his possession by that point.

Martin was killed Friday in an exchange of gunfire with police. He was going to be fired from his workplace, the manufacturing plant where he made his attack, though Zimon said Saturday police are not sure whether he knew he would be let go when he brought his handgun to his job Friday morning. "[W]e can surmise that he was speculative about what was going to happen as evidenced by him arming himself with a firearm," she said.

The identities of the five people Martin killed have been released; all were fellow workers at the plant. Of the six police officers wounded, three remain hospitalized, but all are in stable condition. Bonnie Kristian

Acting U.S. Defense Secretary Patrick Shanahan said Saturday he has yet to choose which military projects may have funding reallocated to pay for border wall construction following President Trump's national emergency declaration.

The Trump administration reportedly identified $3.6 billion from the military construction budget and $2.5 billion from a Defense Department drug interdiction fund, but Shanahan has ultimate approval on how much can be taken from which programs. "Very deliberately, we have not made any decisions," Shanahan said.

One military official told Reuters Shanahan is likely to approve the targeted amount from the construction budget. But Shanahan said that one area that will not be touched is military housing, which has come under scrutiny lately for poor standards.

The Pentagon is also still reviewing whether the wall is necessary to support the use of armed forces. Tim O'Donnell

President Trump on Twitter late Saturday asked the United States' European allies to collect and contain hundreds of Islamic State fighters the United States has captured in Syria:

The fighters in question are Europeans who traveled to the Mideast to back the Islamic State. In some cases, "fighter" may not be a fair characterization; for example, a London teenager named Shamima Begum, now 19, recently gave birth after traveling to Syria in 2015 to marry an ISIS militant. She may never have personally acted as a combatant and now seeks to return to the United Kingdom.

While France will repatriate and, in some cases, prosecute French nationals among these captured hundreds of ISIS affiliates, other nations, most notably the United Kingdom, have been less willing to do so with ISIS recruits from their countries. The situation is coming to a head as the fight against ISIS in Syria winds down; U.S.-backed Syrian forces said Saturday the terrorist group today controls just 700 square meters of Syrian territory. Bonnie Kristian