In the best-case scenario, the commission will decide based on the report that both Romania and Bulgaria have fulfilled all criteria and are on track to join the EU on January 1, 2007, as scheduled.
Or, the report could recommend delaying the entry of one or both countries for one year, until 2008, if it concludes they have yet to meet all demands. The accession treaty provides for a "safeguard clause" which allows the EU to delay the entry of either country by one year, provided the commission deems them clearly unprepared.
As a third option, the report could suggest the two states be invited to join in January 2007 but on condition they meet outstanding criteria by the end of September.
Analyst Joan Hoey, of the London-based Economist Intelligence Unit, told RFE/RL that she thinks a delay until 2008 is unlikely for either of the countries.
"First of all, although the official position of the commission is each country will be judged on their own merit, the implication being that one could join and the other could be delayed, I don't really think that is on the agenda, and they will either join together in 2007 or not at all," she said.
"And our assumption is that they will join together in January 2007, because to delay either one of these countries would be such a humiliation and not least would I think present a major political headache for the commission," Hoey added.
But Hoey did say that the commission might opt for the third option, where progress would have to be assessed again at the end of September.
Problems With Corruption, Lack Of Reform
Because of lack of preparedness, Romania and Bulgaria missed the 2004 enlargement wave, when 10 mostly East European countries joined the bloc. Both countries, especially Romania, were seen back then as having major problems with corruption, and an unreformed judiciary and administration.
The commission's previous report, in October 2005, gave Romania 14 "red flags" for serious shortcomings in several areas. Those pertaining to corruption and border-security issues were deemed serious enough to delay membership.
But Romania over the past year has made considerable progress in reforming its judicial system and fighting corruption, managing to move ahead of Bulgaria in the race to fulfill the admission criteria.
The commission is now likely to praise Romania for its high-level corruption investigations, which have brought charges against public officials, judges, and even top politicians. The targets include former Prime Minister Adrian Nastase and current Deputy Prime Minister George Copos.
"It is certainly the case that Romania has made a lot of progress over the past few years and has maybe acted with more urgency in some of the areas for concern to the extent that many of the red flags that were identified in the last commission report back in October 2005 have now turned to green," Hoey noted.
New, More Technical Concerns
On May 16, Romania is expected to get red flags mainly for technical shortcomings, such as on computerized tax collection and food safety.
Both Romania and Bulgaria will be warned that they could miss out on billions of euros in EU aid because of the lack of systems to receive and monitor EU farm subsidies
But Bulgaria is expected to get six red flags in much more sensitive areas, including corruption, organized crime, and money laundering. This will probably confirm increasing EU dissatisfaction with Bulgaria's lack of progress in reforming its judiciary and fighting corruption.
Bulgarian Mafia Wars
Organized crime and corruption continue to flourish in Bulgaria despite EU warnings. Two high-profile killings last week, apparently contract killings, were only the latest in what analysts say is a turf war between powerful and well-connected organized-crime groups.
However, analyst Hoey thinks Bulgaria is not so far behind Romania in preparations. "At the end of the day, I think the distinction, to make a really hard and fast distinction between the two countries, I would not say that in qualitative terms Romania is so far ahead of Bulgaria in the area of justice and home affairs, that's the area which has been singled out for Bulgaria with a red flag," she said.
However, Bulgarian Prime Minister Sergei Stanishev recently warned Brussels not to humiliate his country, saying a possible delay in EU membership could cause an anti-EU backlash and bring reform to a standstill.
Both Barroso and EU Enlargement Commissioner Olli Rehn are due to visit Romania and Bulgaria on May 17 to explain whatever decision the commission will announce the day before.
The announced visits are seen by some as an endorsement of EU's support for both countries' early membership. But some skeptics in both Bucharest and Sofia say the visits might only be meant to comfort Romanians and Bulgarians in case the offer falls short of full membership on January 1, 2007.