WASHINGTON — Senate Republicans will try a second time on Tuesday to move ahead on a resolution rejecting the Iran nuclear deal, and the outcome is expected to be the same: Democrats are poised to block the measure and preserve President Barack Obama’s foreign policy win.

Last week, Senate Democrats blocked GOP attempts to get a disapproval resolution to Obama’s desk and House Republicans settled for passing two related measures that are never expected to get out of Congress.

The international accord backed by the United States, Iran and five world powers would curb Iran’s nuclear program in exchange for relief from crippling sanctions that have undercut Tehran’s economy.

Senate Majority Leader Mitch McConnell, R-Ky., has scheduled another vote Tuesday to end debate, but that motion is likely to be blocked by Senate Democrats as well. It’s unclear if this is the last vote the Republican-led Senate will take on the Iran nuclear deal.

Republicans now are working to craft new sanctions legislation to maintain a hardline stance against Iran. Looking ahead to next year’s elections, Republican campaign committees also have targeted Democrats who backed the deal and some organizations against the deal already have threatened to withdraw political contributions from members of Congress who backed it.