The US Senate is due to vote on Tuesday or Wednesday on whether Montenegro joins NATO. Photo: Pixabay.

The full US Senate is set to start a day-and-a-half debate on Tuesday on the treaty to allow Montenegro’s membership in NATO.

This follows a 97-2 procedural ballot in the Senate on Monday in favour of allowing the final vote this week on the ratification of Montenegro’s NATO Accession Protocol.

Now lawmakers have a maximum of 30 hours to debate whether Montenegro should become the 29th member of the Western alliance.

A two-thirds majority in the 100-member Senate is required and the final vote is expected late on Tuesday or on Wednesday.

The senators are expected to back Montenegrin accession, and although votes are still required in parliaments in the Netherlands and Spain, the government in Podgorica hopes the process will be complete by May when the next NATO summit is scheduled.

The only two ‘no’ votes in the procedural ballot on Monday came from Republican Senators Rand Paul and Mike Lee, both of whom had been blocking the progress on the vote for several months.

Paul warned Washington against spreading itself too thinly at a point when its military is involved in Iraq, Syria, Libya and Yemen.

“Montenegro in NATO will antagonise Russia while doing nothing to advance US national security,” Paul said during the floor debate.

“Most Americans can’t find Montenegro on a map,” he added in a sharply-worded Senate speech.

“Are you willing to send your kids there to fight?” he asked.

Paul has suggested that recruiting Montenegro, which had once been a staunch Russian ally, could lead to heightened tension with Moscow, possibly even war.

The Senate vote came after US Secretary of State Rex Tillerson on March 21 wrote to senators urging them to ratify Montenegro’s membership, saying it was “strongly in the interests of the United States”.

Tillerson argued that Montenegro’s membership would support the country’s democratic reform, trade, security and foster stability among its neighbours.

“Montenegro’s participation in the May NATO Summit as a full member, not as an observer, will send a strong signal of transatlantic unity,” Tillerson wrote.

Moscow strongly opposes the expansion of NATO to the east, including the Balkans, however, and the delay in US approval of Montenegro’s protocol had raised doubts about whether Donald Trump’s new administration was ready to stand up to Russia over the issue.

All 28 of NATO’s members must ratify Montenegro’s accession protocol before it can join the alliance. Only three members have not approved it yet, Spain, the Netherlands and the US.

Russia’s allies and Kremlin followers in Montenegro had hoped that Trump’s friendlier attitude towards Moscow could mean ratification being blocked.

Montenegro gained NATO candidate status in 2010.

Accession still remains a highly controversial issue inside the country. An opinion poll conducted in December 2016 had only 39.5 per cent of Montenegrins in favour of NATO membership.