By Megan Cassella WASHINGTON (Reuters) – Republican presidential candidate Marco Rubio racked up a number of endorsements from party leaders on Monday, giving weight to his message that he can become the establishment favorite behind whom Republicans can unite. Arkansas Governor Asa Hutchinson, U.S. Senator Orrin Hatch of Utah and former Republican presidential candidate Bob Dole said they would back the U.S. senator from Florida for the party's nomination to run for president in the Nov. 8 election. Three Republican leaders from Nevada – U.S. Senator Dean Heller and U.S. Representatives Cresent Hardy and Mark Amodei – also announced their support for Rubio leading up the state's caucuses on Tuesday.