Trump had refused to rule out a third-party run during the Aug. 6 Republican debate.
NEW YORK -- Donald Trump will sign a pledge to back the Republican presidential nominee and not to run as an independent should he not win the party's nomination, multiple outlets have reported.
00:23 Civil rights icon skipping museum opening because President Trump is expected to attend22
04:37 Trump expected to sign waiver on embassy move to Jerusalem after recognizing it as Israel’s capital33
03:44 SEE IT: Trump slurs words in Jerusalem embassy speech35
16:41 The Texas man behind one of the most popular anti-Trump signs in 201735