Watchers of Middle East politics were quick to take note of a line in President Obama’s address before the Turkish Parliament on Monday in Ankara, in which he mentioned “Annapolis.”

By bringing up the word, Mr. Obama was sending a warning to the government of new Israeli Prime Minister Benjamin Netanyahu that reneging on the goals outlined during the Annapolis Middle East peace conference in 2007 would put Mr. Netanyahu on the wrong foot with the Obama administration.

The issue sprouted last week when Israel’s hawkish new foreign minister, Avigdor Lieberman, said that agreements reached at the American-sponsored peace conference in Annapolis, Md., have “no validity.” Mr. Lieberman said that the Israeli government “never ratified Annapolis, nor did Parliament.”

The aim of the Annapolis process, as it became known, was to agree on the framework for a Palestinian state alongside Israel by the end of 2008, a goal which was never reached.

Mr. Obama had not referred to the Annapolis conference in any of his major public remarks on Mideast peace since he took office.

But there he was on Monday, directly rebutting Mr. Lieberman’s comments in his most high-profile address about America’s relationship with the Muslim world, before Turkish legislators. He would push for a two-state solution, Mr. Obama said, despite the view of many foreign policy experts that such a goal will be even more difficult to reach because of the makeup of the new Israeli government under Mr. Netanyahu, not to mention the fractured state of internal Palestinian politics.

“Let me be clear: the United States strongly supports the goal of two states, Israel and Palestine, living side by side in peace and security,” Mr. Obama said. “That is a goal that the parties agreed to in the road map and at Annapolis. That is a goal that I will actively pursue as president.” The road map refers to a 2003 outline of steps toward a peace agreement.

Asked why Mr. Obama suddenly decided to start tossing the word “Annapolis” around, Denis McDonough, the deputy national security adviser for strategic communications, did not elaborate much, apparently deciding to let his boss’s statement speak for itself. “I think the president is speaking directly about his views and his hopes for relations among Israelis and Palestinians, as well as his hopes for a broader Arab-Israeli peace,” Mr. McDonough said.

But privately, several administration officials and Middle East experts said that Mr. Obama is girding for a protracted showdown with the new Israeli government over the pursuit of Palestinian statehood.

Taken by themselves, Mr. Lieberman’s comments are not that significant, many foreign policy experts said, because most Israeli foreign ministers are not that relevant to the peace process; that portfolio is usually held by the prime minister. Tzipi Livni, the former foreign minister, broke that mold somewhat, when she demanded the portfolio and got it, but even she was eventually usurped there by Ehud Olmert, a former prime minister.

The bigger issue for the Obama administration is whether Mr. Lieberman is channeling Mr. Netanyahu, the man who is likely to control the peace process file. Mr. Netanyahu is viewed as a hawk, but one who is capable of being dragged to the peace table, as President Clinton did when he pushed and prodded him to continue peace negotiations at the Wye River Plantations after former Prime Minister Yitzhak Rabin was assassinated.

By forcefully rebutting Mr. Lieberman’s repudiation of Annapolis, and in such a public fashion, Mr. Obama is issuing a warning to Mr. Netanyahu that the United States will push for a two-state solution, and will expect him to publicly articulate his own support for such an initiative, many experts said.

“At a minimum, Bibi will need to disown these statements and come out explicitly in support of the two-state solution before his meeting with President Obama,” said Ghaith Al-Omari, a former Palestinian negotiator who now works with the American Task Force on Palestine. “If not,” Mr. Al-Omari said, “the issue will become the focus of the meeting.”

Fresh from his first overseas trip as president—a weeklong trip in which he drew stellar reviews—Mr. Obama may soon be jetting off again. He has a series of trips, both announced and unannounced planned, and will also be hosting several overseas visitors to the White House. Somewhere in all of that will be a first meeting between Mr. Obama and Mr. Netanyahu; it’s bound to be pretty interesting.