The re-emergence of Sri Lanka's controversial former president, Mahinda Rajapaksa, as the leader of the main opposition alliance in the country's general elections in August, and as potential prime minister, appears to signal the end of the country's brief democratic honeymoon and a return to divisive politics as usual.

Former Sri Lankan president Mahindra Rajapaksa. (Flickr/Mahindra Rajapaksa.)

Six months after his stunning victory in Sri Lanka's presidential election, Maithripala Sirisena faces a renewed challenge from the man he ousted. Sirisena's triumph gave new life to Sri Lanka's battered democracy, which had suffered under Rajapaksa's authoritarian and nepotistic regime. Rajapaksa's likely return to parliament with a significant degree of support will put continued political reforms and chances for ethnic reconciliation under severe pressure.

Risking his career, Sirisena left his position as health minister and general secretary of the ruling Sri Lanka Freedom Party (SLFP) in November 2014 to head a combined opposition campaign led by the United National Party (UNP) to unseat Rajapaksa. Running on promises to root out corruption and re-establish the rule of law, Sirisena won a large portion of the Sinhala majority's vote, and overwhelming support from minority Tamils and Muslims. 

Since coming into power, he has moved away from Rajapaksa's narrative of Sinhala nationalism – which underpinned the government's brutal 2009 victory over the Tamil Tiger insurgency – and returned power to the office of the prime minister and parliament. He has also taken tentative steps to rebuild relations with minorities by addressing some of their long-standing grievances.

Still, the political, ethnic and religious wounds that split the country remain largely unhealed, and the unfulfilled reform agenda is long. This includes not just accountability and the need for a negotiated settlement to ethnic divisions, but also a comprehensive plan for demilitarisation, a determined drive to bring the scores of major corruption investigations to completion, and further reforms to rebuild Sri Lanka's heavily politicised justice and policing system.

Even if Rajapaksa's alliance doesn't win enough seats to secure him the prime minister's office, his leadership of the Sinhala nationalist bloc in parliament will exacerbate communal divisions and pose a major challenge to further reform. 

In a 1 July speech announcing his candidacy, Rajapaksa called on 'patriotic forces' to protect 'the motherland'. He accused Sirisena's UNP-led Government of undermining national security, supporting terrorists and ruining the economy. These have been the themes of a series of large rallies throughout Sinhala-majority areas of the country since mid-February, which have called on Sirisena to bring back Rajapaksa as prime minister. Rajapaksa remains popular with large numbers of Sinhala voters, particularly in rural areas.

Within days of his victory in January, Sirisena took over leadership of the SLFP from Rajapaksa, and the former also gained leadership of the SLFP-led coalition, the United People's Freedom Alliance (UPFA). But despite substantial concessions, he never gained complete control over either group, most of whom see Rajapaksa as their only chance to prevent a landslide UNP victory in August. Sirisena has struggled to hold the party and alliance together, while blocking Rajapaksa from returning to parliament with either the SLFP or UPFA.

The announcement on 3 July that the UPFA had decided to nominate Rajapaksa as a candidate shocked and disappointed Sirisena's supporters, and appeared to signal Sirisena's capitulation in his battle with Rajapaksa. Behind-the-scenes attempts reportedly continue for the smaller pro-Sirisena wing of the SLFP to contest separately from the UPFA, or to run with the UNP, but with less than a week to finalise candidate lists and party nominations it will be hard to reconstitute anything like the January coalition that stood against Rajapaksa. 

The appeal of Sinhala nationalist ideas and the continued popularity of Rajapaksa has considerably limited Sirisena's boldness during his first six months in office. In the last parliament, which Sirisena dissolved on 26 June, UPFA legislators were able to block many of Sirisena's initiatives. UPFA resistance watered down what still became Sirisena's chief achievement to date, a constitutional amendment reducing the powers of the presidency. 

Fear of upsetting nationalist sentiments and giving Rajapaksa and his allies political ammunition has meant Sirisena's gestures on reconciliation with Tamils – returning land held by the military and reducing its role in Sri Lanka's north and east; releasing political detainees and investigating the thousands who disappeared during the course of the war – have been partial and ad hoc. 

To avoid inflaming Sinhalese opinion and angering the powerful military, Sirisena and his allies in the UNP have also held off announcing plans for the domestic accountability mechanism for alleged war crimes that they promised both voters and the UN. A report from a UN inquiry into the allegations, postponed by the UN Human Rights Council in February at the new government's request, is due to be released by early September. Rajapaksa and his allies flatly reject any suggestion of accountability or cooperation with the UN, and the subject is likely to feature as a key issue of the campaign.

The coming campaign is set to be close, and possibly violent. While the UNP is still favoured to win the largest number of seats and to form the next government, many fear that once back in parliament, Rajapaksa and his powerful family will be able to chip away at the UNP's numbers until he is able to form a majority. It remains unclear what, if any, role Sirisena will play in the campaign. But unless there is another surprising reversal, his credibility as the leader of the movement for democratic reforms and reconciliation has been badly damaged.

Sirisena's first six months in office have proven just how entrenched Sri Lanka's post-war challenges are. Hopes for January's democratic 'revolution', especially in the international community, were always overblown. But to preserve the possibility of slower, more incremental, progress, Sirisena will need a renewed commitment to his campaign principles, and some luck.