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--> A midday take on what's happening in politics and how to have a sense of humor about it.*

*Ha. Haha. Hahah. Sniff. Haha. Sniff. Ha--breaks down crying hysterically.

The Hill's 12:30 Report: Fallout from Nielsen's ouster | Trump looks to get tougher on border security | How Nielsen left | What we know about her replacement | Trump labels Iran's Revolutionary Guard a terror group | This week in Congress: Barr testifies, net neutrality vote | Why Dems covet John Lewis John LewisDemocrats urge Biden to resist filibuster, court-packing calls Rep. Bill Pascrell named chair of House oversight panel The Hill's Campaign Report: Biden goes on offense MORE' 2020 endorsement | NY bill would release Trump's state tax returns | National Empanada Day

TALK OF THE MORNING

Annnnnd goodbye:

Kirstjen Nielsen Kirstjen Michele NielsenDHS IG won't investigate after watchdog said Wolf, Cuccinelli appointments violated law Appeals court sides with Trump over drawdown of immigrant protections Democrats smell blood with new DHS whistleblower complaint MORE is leaving her post as Homeland Security secretary after a tumultuous 16-month tenure carrying out President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE's hard-line immigration policies. http://bit.ly/2KhWce4

How it happened: Nielsen met with Trump to discuss "a path forward" on the border. The meeting did not go well, and the president asked her to resign. https://nyti.ms/2D0gCSA

The announcement: President Trump made the announcement on Twitter. "I would like to thank her for her service," Trump said in the announcement.

Read Nielsen's resignation letter: http://bit.ly/2D2GBZz

When Nielsen will leave: On Wednesday, giving her time to iron out details of the transition.

Timing: Nielsen's departure comes two days after Trump abruptly withdrew his nominee to lead Immigration and Customs Enforcement because he decided "to go in a tougher direction." http://bit.ly/2YUINvA

NIELSEN'S REPLACEMENT:

President Trump announced that Customs and Border Protection Commissioner Kevin McAleenan will take over as acting Homeland Security secretary until the president appoints a new secretary. What to know about him: http://bit.ly/2UEnuz8

Why this is an interesting choice: By law, acting Deputy Secretary Claire Grady is in line to succeed Nielsen. The White House will have to fire her to make McAleenan the acting secretary. https://nyti.ms/2D0gCSA

Nielsen's permanent replacement: Possible replacements include former Virginia Attorney General Ken Cuccinelli and Energy Secretary Rick Perry Rick PerryEnergy secretary questions consensus that humans cause climate change OVERNIGHT ENERGY: Democrats push resolution to battle climate change, sluggish economy and racial injustice | Senators reach compromise on greenhouse gas amendment stalling energy bill | Trump courts Florida voters with offshore drilling moratorium OVERNIGHT ENERGY: Trump signs major conservation bill into law | Senate votes to confirm Energy's No. 2 official | Trump Jr. expresses opposition to Pebble Mine project MORE. http://bit.ly/2YYMujO

New reporting -- family separations led to Nielsen's ouster:

Via NBC's Julia Ainsley and Geoff Bennett, "President Donald Trump has for months urged his administration to reinstate large-scale separation of migrant families crossing the border, according to three U.S. officials with knowledge of meetings at the White House. Trump's outgoing Homeland Security secretary, Kirstjen Nielsen, resisted -- setting her at odds with the president." New details: https://nbcnews.to/2U45UA3

Keep in mind, via Julia Ainsley: "Important note: Sources say Nielsen opposed reinstating family separation for legal reasons, not for moral reasons." http://bit.ly/2Vxu1bV

Just now — Nielsen briefly spoke:

Homeland Security Secretary Kirstjen Nielsen made a brief comment outside of her home on Monday her first public remarks since resigning. "I share the president’s goal of securing the border," Nielsen said. "I will continue to support all efforts to address the humanitarian and security crisis on the border, and other than that I'm on my way to keep doing what I can for the next few days."

It's Monday. I'm Cate Martel with a quick recap of the morning and what's coming up. Send comments, story ideas and events for our radar to cmartel@thehill.com -- and follow along on Twitter @CateMartel and Facebook .

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NEWS THIS MORNING

Getting traction -- Not about that open border life:

"Sen. Bernie Sanders Bernie SandersButtigieg stands in as Pence for Harris's debate practice Bernie Sanders warns of 'nightmare scenario' if Trump refuses election results Harris joins women's voter mobilization event also featuring Pelosi, Gloria Steinem, Jane Fonda MORE (I-Vt.) on Sunday shot back at those who suggest he supports open borders, saying high levels of global poverty would make an open borders policy complicated." http://bit.ly/2G9dTbz

What Bernie does think should happen: "I think what we need is comprehensive immigration reform. ... Oh my god, there's a lot of poverty in this world, and you're going to have people from all over the world. And I don't think that's something that we can do at this point. Can't do it."

Some context: The majority of 2020 Democrats, including Sanders, have not released an immigration platform yet.

Watch Sanders's full response to the question about open borders: http://bit.ly/2G9dTbz

Tax returns, we're comin' for ya:

Via The New York Times's Jesse McKinley, New York state lawmakers are planning to introduce a bill to release President Trump's tax returns. Specifically: State tax returns, not federal returns. https://nyti.ms/2G7WK1N

THE ACTING WHITE HOUSE CHIEF OF STAFF WEIGHED IN ON THE TAX RETURNS: Acting White House chief of staff Mick Mulvaney Mick MulvaneyMick Mulvaney to start hedge fund Fauci says positive White House task force reports don't always match what he hears on the ground Bottom line MORE said on "Fox News Sunday" that Democrats will "never" see President Trump's tax returns. "Nor should they. That's an issue that was already litigated during the election. Voters knew the president could have given his tax returns, they knew that he didn't, and they elected him anyway." http://bit.ly/2G2kvqX

IN THE WHITE HOUSE

A new terror group:

This morning, the Trump administration announced that it has labeled Iran's Revolutionary Guard a "foreign terrorist organization." http://bit.ly/2UJiGsf

Why this is especially newsy: It is the first time the United States has labeled an entire government entity as a foreign terrorist organization.

Trump said in a statement: "This action sends a clear message to Tehran that its support for terrorism has serious consequences. We will continue to increase financial pressure and raise the costs on the Iranian regime for its support of terrorist activity until it abandons its malign and outlaw behavior."

IN CAMPAIGN NEWS

The trophy endorsement:

Via The Hill's Jonathan Easley, Democrats who are running for president in 2020 are vying for an endorsement from Rep. John Lewis (D-Ga.). In an interview for The Hill, Lewis said "several" 2020 candidates have reached out for advice or an endorsement. http://bit.ly/2I3SHWs

Where Lewis stands: "The iconic civil rights leader, who switched his endorsement from Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE to Barack Obama Barack Hussein ObamaMichelle Obama and Jennifer Lopez exchange Ginsburg memories Pence defends Trump's 'obligation' to nominate new Supreme Court justice The militia menace MORE in 2008, is holding off on backing a candidate as he considers the massive field of contenders."

THIS WEEK IN CONGRESS

The net neutrality fight is back: House Democrats are reviving a fight over Obama-era net neutrality rules. They will try to vote on a bill restoring the rules this week.

White nationalism: The House Judiciary Committee is holding a hearing on hate crimes and white nationalism and will hear from tech industry executives on how to crack down online.

Budget: The House may take up legislation to lift spending caps by $133 billion in two years.

Democrats have their retreat: House Democrats are heading to Leesburg, Va., from Wednesday to Friday for their annual retreat.

William Barr Bill BarrProsecutor says no charges in Michigan toilet voting display Judge rules Snowden to give up millions from book, speeches The Hill's Morning Report - Sponsored by Facebook - Washington on edge amid SCOTUS vacancy MORE is in the House (and Senate): Attorney General William Barr is slated to testify before the House and Senate appropriations committees to discuss the 2020 budget. Yeah, but: Barr will almost certainly face questions related to his four-page summary of special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's investigation report.

Nominations: Republicans are expected to power through nominations after going "nuclear" and clearing hurdles for confirmation.

Context and details for each from The Hill's Jordain Carney and Juliegrace Brufke: http://bit.ly/2I5jlOH

NOTABLE TWEETS

Lol:

peak Monday Senate https://t.co/bHdtRNQeFp — Jordain Carney (@jordainc) April 8, 2019

ON TAP

The House is in. The Senate will meet later today. President Trump and Vice President Pence are in Washington, D.C.

11:45 a.m. EDT: President Trump participated in a credentialing ceremony for newly appointed ambassadors.

12:30 p.m. EDT: President Trump has lunch with Vice President Pence.

1:45 p.m. EDT: President Trump receives an intelligence briefing.

2:30 p.m. EDT: President Trump meets with Secretary of State Mike Pompeo Michael (Mike) Richard PompeoOvernight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers Overnight Defense: House Democrats unveil stopgap spending measure to GOP opposition | Bill includes .6B for new subs | Trump issues Iran sanctions after world shrugs at US action at UN Navalny calls on Russia to return clothes he was wearing when he fell ill MORE.

4 p.m. EDT: Vice President Pence meets with the vice president of Brazil.

4 p.m. EDT: The Senate meets.

6:30 p.m. EDT: First votes in the House.

WHAT TO WATCH

5 p.m. EDT: The House Rules Committee discusses a bill on net neutrality and a bill on the debt and deficit. Livestream: https://cs.pn/2WU8DOE

NOW FOR THE FUN STUFF...

Today is National Empanada Day.

Portland, Maine, is quite fruitful:

Nine nurses in the same labor unit at Maine Medical Center are pregnant and due around the same time. https://bzfd.it/2Uor3dj

Photo of eight of the nine pregnant nurses: http://bit.ly/2YUL9uq