President Barack Obama's decision to send his top diplomat on an emergency Middle East peacemaking mission Tuesday marked an administration shift to a more activist role in the region's affairs and offered clues to how he may use the political elbow room afforded by a second term.

The move could pay dividends quickly if Secretary of State Hillary Rodham Clinton helps arrange an end to the conflict between Israel and Hamas. She was scheduled to head to Cairo on Wednesday for talks with Egyptian President Mohamed Morsi after discussions with Israeli Prime Minister Benjamin Netanyahu.

Clinton's peacemaking trip is Obama's clearest signal yet to Israel that it should begin to pull back its campaign against militants in the Gaza Strip. The administration knows that with Clinton on the ground trying to resolve the crisis, it will be harder for Netanyahu to make good on his threat to invade Gaza.

Obama and his administration have expressed full support for Israel since the conflict began last week, but diplomatic pressure is building for a cease-fire that would end Israeli airstrikes and Hamas rocket attacks, both of which are killing civilians.

Israel says it is pressing its air campaign in Gaza to reduce the militants' ability to fire rockets into Israel.

The international diplomatic push to end the Gaza offensive appeared to gain momentum early Tuesday, with Morsi predicting that attacks would soon end and Netanyahu saying Israel would be a "willing partner" in a cease-fire with Palestinian militants in Gaza. But the Israeli leader later made it clear he was not ruling out a ground invasion.

If Egypt was to succeed in brokering a cease-fire or a temporary calming of tensions, Clinton's presence would add diplomatic heft to make it stick. She could also congratulate the new Islamist government there for upholding Egypt's 30-year position as a peacemaker, a bottom-line goal for the United States as it remakes its relationship with Cairo after the fall of U.S.-backed autocrat Hosni Mubarak.

"In the days ahead, the United States will work with our partners here in Israel and across the region for an outcome that bolsters security for the people of Israel, improves conditions for the people of Gaza and moves toward a comprehensive peace for all peoples of the region," Clinton said before a late-night meeting with Netanyahu in Jerusalem.

She was also to see Palestinian Authority President Mahmoud Abbas before heading to Cairo, where U.S. officials are hopeful a deal can be announced. Clinton will not see any representatives of the Palestinian Hamas faction that controls Gaza and pledges armed resistance against bordering Israel.

Clinton rushed to Israel after Obama dispatched her from Cambodia, where she was accompanying him on his Asia trip. Her entry follows days of intensive telephone diplomacy, including three conversations in two days between Obama and Morsi.

"Sometimes there's no substitution for showing up," State Department spokeswoman Victoria Nuland said Tuesday. "The president and she obviously thought that her going and actually sitting down with leaders — with Prime Minister Netanyahu, with President Abbas and with President Morsi — could help de-escalate the situation. So it was obviously important to leave no stone unturned."

Clinton has rarely been involved directly in Middle East peace talks in the first Obama term. Her two-day visit to the region is a potentially risky high-water mark for direct U.S. engagement in the Israeli-Palestinian issue by an administration that has kept the Middle East's core conflict at arm's length.

Since his reelection, Obama has said he hopes to play a role in Middle East peacemaking but has not proposed any new plan. His relations have been strained with both Netanyahu and Abbas, who leads the moderate Palestinian wing.

Obama may have more leverage with Netanyahu than he did when the two got off to a rocky start four years ago and American backers of Israel wondered aloud whether Obama was sufficiently committed to their cause.

The president has given solid backing for the Israeli leader's security demands, including a pledge to attack Iran if necessary to stop that country from gaining a nuclear weapon. Obama also backed Israel when Abbas attempted to gain U.N. recognition for a Palestinian state.

The Obama administration refused to spell out Clinton's goals beyond helping to secure an end to violence. But U.S. officials said they hope a resolution of the current conflict could lay the groundwork for talks on a comprehensive peace deal.

Israel has resisted calls for a cease-fire that its leaders fear Hamas militants would quickly break. Because Israel has not publicly backed any plan, the United States would say only that it seeks a "durable solution."

"If there is a possibility of achieving a long-term solution to this problem through diplomatic means, we prefer that," Netanyahu said in welcoming Clinton. "But if not, I am sure you understand that Israel will have to take whatever action is necessary to defend its people. This is something that I don't have to explain to Americans. I know that President Obama, you and the American people understand that perfectly well."

Israel demands an end to rocket fire from Gaza and a halt to weapons smuggling into Gaza through tunnels under the border with Egypt. It also wants international guarantees that Hamas will not rearm or use Egypt's Sinai region, which abuts Gaza and southern Israel, to attack Israelis.

Hamas wants Israel to halt all attacks on Gaza and lift tight restrictions on trade and movement in and out of the territory that have been in place since Hamas seized Gaza by force in 2007. Israel has rejected such demands in the past.