By Luiza Ilie and Radu-Sorin Marinas
BUCHAREST (Reuters) - Romania's President Klaus Iohannis appointed European Parliament lawmaker Viorica Dancila as prime minister designate on Wednesday, the country's third premier in a year, in move dictated by "parliamentary arithmetic".
The choice will mostly be judged on whether it will hamper or facilitate the European Union state's struggle to stamp out high-level corruption.
The PSD has proposed Dancila, 54, but her close ties with powerful party leader Liviu Dragnea, might have been offputting for the president.
"The strongest argument is parliamentary arithmetic," Iohannis told reporters after holding consultations with all political parties to pick the new prime minister.
"For me it's very clear that the Social Democrats have a majority ... so I weighted all arguments and decided to name their proposal for premier ... I decided to give the PSD another chance," he said, adding a cabinet should be formed by Feb. 1.
An outspoken critic of the ruling Social Democrats'(PSD) record on combating graft, Iohannis urged the party to start deliver on its electoral promise as Romanians have big expectations. Dancila replaces former premier Mihai Tudose, who quit after falling out with Dragnea.
Dragnea is one of a number of ruling coalition members facing trial on graft charges. He denies wrongdoing.
(Writing by Justyna Pawlak; Editing by Alison Williams)