Opponents of the Affordable Care Act protest outside the Supreme Court Wednesday before oral arguments in the second major challenge to be heard by the justices. Jim Lo Scalzo/EPA/Landov hide caption

itoggle caption Jim Lo Scalzo/EPA/Landov

Speaker of the House John Boehner, R-Ohio, leaves the chamber Feb. 3 after another House vote to repeal the Patient Protection and Affordable Care Act. J. Scott Applewhite/AP hide caption

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Jose Ramirez and Mariana Silva speak in December with Yosmay Valdivia (right), an agent from Sunshine Life and Health Advisors, at the Mall of the Americas in Miami about plans available from the Affordable Care Act. Joe Raedle/Getty Images hide caption

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This flea market in Colorado Springs and the Obamacare exchanges are versions of the same thing — marketplaces where sellers display wares and shoppers browse and buy. www.csfleamarket.com hide caption

itoggle caption www.csfleamarket.com

The tax penalty is designed to encourage people to sign up for health insurance. iStockphoto hide caption

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Yolanda Madrid of Miami (left) talks with navigator Daniela Campos while signing up for health insurance under the Affordable Care Act in January. Lynne Sladky/AP hide caption

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Yuvania Maldonado, a counselor for President Obama's health care law, speaks with Chicago taxi driver Mohammad Chaudri at a city office where taxi drivers go to renew their license. M. Spencer Green/AP hide caption

itoggle caption M. Spencer Green/AP