Cuellar also on Wednesday filed for reelection as a Democrat, quieting speculation that he planned to switch parties. On the House floor Wednesday afternoon, numerous Democratic colleagues greeted Cuellar warmly, hugging him and shaking his hand.

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This cycle, he is facing a serious Republican opponent — Webb County Judge Tano Tijerina, a former Democrat, who announced his candidacy Tuesday and noted that Cuellar was facing “serious federal corruption accusations that have shaken the trust of the people he is supposed to serve,” in a statement announcing his candidacy.