After narrowly beating back an attempt to kill a provision designed to encourage new car buying, the Senate passed, 91-5, the $106 billion supplemental war spending bill. The measure will now be sent to President Barack Obama for his signature.

Three Republicans — Sens. Tom Coburn (Okla.), Jim DeMint (S.C.), and Mike Enzi (Wyo.) — along with one Democrat — Sen. Russ Feingold (Wis.) and Independent Sen. Bernie Sanders (Vt.) — voted against the bill.

This measure is likely the last off-budget war funding bill, now that Obama has decided to include money for the wars in Iraq and Afghanistan in his annual budgets.

This year’s supplemental was beset by problems from the beginning, as various factions in both chambers objected to a loan for the International Monetary Fund to language prohibiting the transfer of terrorist suspects from the Guantánamo Bay, Cuba, military prison, and a provision barring the release of photos showing U.S. soldiers abusing detainees in Iraq and Afghanistan.

But the Senate overcame the last hurdle to passage Thursday in a nail-biter vote over the “cash for clunkers— program, which would provide $1 billion in vouchers for consumers seeking to trade in outdated gas guzzlers for newer, more fuel-efficient cars.

By a 60-36 vote, Democrats succeeded in keeping the provision in the war spending bill. Sixty votes were needed to waive points of order against the bill.

Four Republicans — Sens. Kit Bond (Mo.), Thad Cochran (Miss.), George Voinovich (Ohio) and Susan Collins (Maine) — voted with most Democrats to retain the provision and other portions of the bill that could have been struck because they violated the rules for conference reports and emergency legislation. Sen. Ben Nelson (Neb.) was the lone Democrat to vote against his party.

Sen. Maria Cantwell (D-Wash.) initially voted with Nelson, but switched her vote when it was apparent Democrats would not prevail without her.

Republicans had objected to the cash for clunkers program because the cost was not offset. Other Senators, such as Collins and Cantwell, were concerned that the measure did not set fuel efficiency standards for qualifying vehicles high enough to have an effect on the environment.

Collins along with Sen. Dianne Feinstein (D-Calif.) have sponsored a separate measure calling for tougher fuel efficiency standards for new car purchases under the program. Feinstein said she and Collins were promised any extension of the current program would reflect their legislation.

Knowing they would have a tight vote, Democrats used a procedural maneuver that forced the Senate to vote to waive all points of order against the supplemental, rather than voting on a planned Republican point of order against cash for clunkers only.

The provision violated rules prohibiting conferees from inserting legislation that was in neither the House nor Senate version into conference reports. Other points of order might have eliminated funding items not related to the wars in Iraq and Afghanistan, because it was not considered “emergency— funding.

In order to get the bill out of conference and passed by the House, Democratic leaders eliminated the controversial detainee photo language, but that caused Sen. Lindsey Graham (R-S.C.) to threaten to hold up the supplemental and all other Senate business until he felt assured the photos would not be released. Graham, along with Sen. Joe Lieberman (ID-Conn.), were concerned a fresh wave of detainee photos would incite violence against Americans in the Middle East.

Senate Majority Leader Harry Reid (D-Nev.) averted a Senate showdown with Graham, however, by agreeing to pass a stand-along prohibition of the photos’ release on Wednesday evening.

Meanwhile, House leaders — who had originally counted on Republican votes to pass their version of the supplemental — found themselves in a tough position when the House minority balked at the $108 billion in loans to the IMF included in the bill.

With the detainee photo language out, Democrats were able to convince enough anti-war Democrats to support the conference report on Tuesday.

Additionally, House and Senate leaders forged a compromise on detainee transfers from Guantánamo after the White House balked at the bill’s strict prohibition on bringing prisoners to the United States. The final measure will allow the Obama administration to transport detainees to the states for trial only, but not for permanent detention.