As President Trump considers declaring a national emergency in order to secure border wall funding, House Armed Services Committee Chair Rep. Adam Smith, D-Wash., and House Republican Conference chair and Armed Services Committee Member Rep. Liz Cheney, R-Wyo. come to “This Week” Sunday.

Plus, former HUD Secretary and former San Antonio Mayor Julián Castro discusses his potential 2020 Democratic presidential run.

And the Powerhouse Roundtable debates the week in politics, with ABC News Political Analyst Matthew Dowd, “The View” Co-Host Meghan McCain, Chicago Mayor Rahm Emanuel, Collective PAC co-founder Stefanie Brown James and former Michigan Senate candidate John James.

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