Health campaigns have faced big obstacles in efforts to change sexual practices (a billboard in Guyana used to advise men to "wear a fresh condom every time").
A possible confrontation in the Persian Gulf could present new obstacles in efforts to make progress on resolving the dispute over Iran's nuclear program, the most intractable issue in Iran's difficult relations with the West.
The remarkable progress of marriage equality in the past decade makes it clear that neither a legal nor a political strategy alone work; they have succeeded in tandem — legal decisions clearing obstacles, political efforts building a democratic consensus.
The report also described what it portrayed as major obstacles to efforts by the United States and American-led Iraqi forces to halt a small but steady infiltration of foreign fighters from Syria and Iran.
She resigned from State on Feb. 1. Aides to Senator Charles E. Grassley, a Republican of Iowa who has led an inquiry into the matter, say they have faced obstacles in efforts to gather certain information about Ms. Abedin's arrangement and about the rules the State Department applies in approving such arrangements.
Hezbollah's attacks on Israeli troops have posed new obstacles to efforts to restart the suspended peace talks between Israel and Syria, which collapsed last month over Syria's demand for the return of the Golan Heights, territory that Israel captured from Syria in the 1967 Arab-Israeli war.
Until the past few years, three theoretical obstacles hampered efforts to form a satisfactory paradigm in this arena.
Lack of a health information system presented obstacles to efforts to improve the quality of care and reduce mortality.
This challenge highlights one of the obstacles facing efforts to vaccinate against polio, as children must receive multiple doses of the vaccine.
The initial success of Gross et al. [ 5] inspired numerous subsequent studies but obstacles hindered efforts to express recombinant receptors that could bind the desired targets and activate the cytolytic functions of the T cells [ 6].
