A full embrace by Clinton could help Obama as he tries to marshal support from lawmakers -- including many House Democrats who have voiced deep reservations about the United States taking military action in Syria.
It comes as Obama is stepping up his own lobbying campaign, sitting down for interviews with six television news networks on Monday and addressing the nation on Tuesday evening.
Clinton is likely to address Syria during her Monday afternoon appearance at the White House as well as at a speech on Tuesday in Philadelphia, according to a person familiar with her plans.
Clinton will be at the White House for a forum on combating wildlife trafficking, one of the charitable causes she is pursuing at the Bill, Hillary and Chelsea Clinton Foundation. She will be joined by her daughter, Chelsea, as well as by Secretary of the Interior Sally Jewell.
Benjamin J. Rhodes, a deputy national security adviser who accompanied Obama on his overseas trip last week and has been a key adviser on Syria policy, also is scheduled to appear at the wildlife trafficking event, which begins at 1 p.m.
On Tuesday, just two hours before Obama addresses the nation from the White House, Clinton will accept an award from the National Constitution Center in Philadelphia. Clinton has said she would use the appearance to deliver a major address on surveillance policy and transparency issues.