10 things you need to know today: April 7, 2018

A Pentagon memo signed by Defense Secretary James Mattis and released Friday night approves up to 4,000 National Guard members for a "southern border security mission" through the end of September. To start the deployment, Arizona will send 150 National Guard members to police the southern border beginning next week, the state government announced Friday, and Texas will send 250. This is not the first time recent presidents have sent troops to do border patrol; President George W. Bush deployed 6,000 National Guard forces in 2006, and President Obama sent 1,200 in 2010, both claiming the same legal authority President Trump cites now.

The Dow Jones Industrial Average dipped 700 points, more than 2 percent, Friday afternoon as trade war jitters set in once again. The index eventually closed the day down more than 570 points. The tremors come as President Trump has said his administration may impose tariffs on another $100 billion in Chinese imports in response to China's "unfair retaliation" against other new import duties. Top White House economic adviser Larry Kudlow said Friday "this is a moderate, temperate approach that we are taking." A Chinese official said Beijing would "definitely fight back."

White House Chief of Staff John Kelly has advised President Trump to fire Scott Pruitt, The Wall Street Journal and The New York Times reported Friday, as the Environmental Protection Agency chief's mountain of ethics scandals grows ever higher. Also Friday, The Associated Press reported Pruitt has spent millions of EPA funding on a full-time, 20-person security team for himself, a detail about three times larger than his Obama administration predecessor's part-time team. Pruitt is already under scrutiny for a rental arrangement with an energy lobbyist, raises for favored EPA employees, and reassignments for unfavored employees.

President Trump signed a memo Friday evening ordering the end of a policy colloquially known as "catch and release," in which some illegal immigrants are not detained while they await asylum or deportation hearings, a process that can take years. The U.S. only has facilities to detain 40,000 immigrants at a time, and the order directs the Pentagon to determine whether there are military facilities that could be used for this purpose. Immigrants released under this program were those not deemed to be dangerous or a flight risk, including children and people seeking asylum. The White House described the change as a necessary security measure.

The Trump administration imposed new sanctions Friday on Russian targets including seven oligarchs, 17 senior government officials, 12 companies, and one state-owned company and its subsidiary bank. The measures are intended to punish Russia for "a brazen pattern of worldwide malign activity," an unnamed administration official told The New York Times. The targets are considered beneficiaries of Russian President Vladimir Putin's administration. The sanctions are authorized by legislation passed by Congress last year, and they are expected to heighten U.S.-Russia tensions.

Former Trump campaign chair Paul Manafort, who was indicted for financial crimes in connection to Special Counsel Robert Mueller's Russia probe, on Friday in court filings accused the FBI of searching his property in violation of Fourth Amendment protections. Shortly after Mueller was appointed, agents visited a storage locker belonging to Manafort's company. They were given access by an employee who did not have authorization to grant it, Manafort's attorneys allege, and returned the following day to take files wielding a warrant secured using information based on that initial access.

Rep. Blake Farenthold (R-Texas) abruptly announced his resignation from Congress Friday afternoon. In December, Farenthold publicly apologized after reports that he was verbally abusive to his staffers; at the time, he also dropped his plans to run for re-election this fall. "While I planned on serving out the remainder of my term in Congress, I know in my heart it's time for me to move along and look for new ways to serve," Farenthold said in a statement Friday. Texas Gov. Greg Abbott (R) will likely call a special election to fill Farenthold's seat until January.

The Department of Justice on Friday seized Backpage.com, a classified ads website. While many of the site's listings are similar to what one would find on Craigslist, the DOJ says Backpage also hosts ads facilitating sex trafficking and prostitution. Backpage was previously under congressional investigation, after which it edited its listing policies. Visitors to the site and its affiliates will now see a notice of seizure from the FBI, the IRS, and several other agencies. The statement describes the seizure as part of an "enforcement action" but provides no further details.

Facebook on Friday announced it will begin verifying the purchasers of political ads on its platform. The social network will require a confirmation of advertisers' identities and locations, and it will also label political ads with their purchasers' names. "This will make it much harder for people to run pages using fake accounts, or to grow virally and spread misinformation or divisive content that way," said CEO Mark Zuckerberg. He is set to testify about data privacy before Congress next week.

At least 14 people were killed and another 14 critically injured when a bus carrying a junior hockey team crashed in Canada's Saskatchewan province Friday evening. The bus was hit by a truck while heading to a playoff game. Junior hockey is for players aged 16 to 20, and the bus was carrying 28 people, including the driver. "I cannot imagine what these parents are going through, and my heart goes out to everyone affected by this terrible tragedy," said Canadian Prime Minister Justin Trudeau.