Arizona Sens. Kyrsten Sinema, Mark Kelly tour Yuma border

Arizona Sen. Kyrsten Sinema lead a group of U.S. senators to the southern border on Jan. 10. Tuesday's visit to Yuma follows the bi-partisan group's tour in El Paso, Texas, where resources are strained from a flood of migrants.

What Kyrsten Sinema’s switch means for the Senate

Sinema says she won’t caucus with Senate Republicans, so Democrats will still hold the majority next year. And she is expected to continue casting most of her votes with Democrats while separating herself on certain issues.

Arizona Sen. Sinema defends bipartisanship at McConnell Center

"More and more it seems like Americans are being told that in order to be a member of either political party, you must adhere to a strict set list of policy viewpoints," Sinema said. "But I don’t think that’s how a majority of Arizonans or Kentuckians or everyday Americans think."