Former vice-president is attracting support of 34% of voters compared to Elizabeth Warren’s 19% and Bernie Sanders’ 16%

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2.31pm BST

Trump announced in a tweet that he would deliver a statement from the White House at 11 a.m. E.T. on the situation in Syria.

Big success on the Turkey/Syria Border. Safe Zone created! Ceasefire has held and combat missions have ended. Kurds are safe and have worked very nicely with us. Captured ISIS prisoners secured. I will be making a statement at 11:00 A.M. from the White House. Thank you!

Tuesday’s developments more concretely define the size and scope of the area that Turkish soldiers will occupy, adding to pockets of northern Syria that Turkey seized from Islamic State and Kurdish fighters in operations in 2016 and 2018.

The deal was widely perceived as good news for Ankara and a poor result for the Kurdish-led Syrian Democratic Forces (SDF), building as it does on the US’ agreement last week that Turkey has a right to a buffer zone on its border at their expense. Most of all, it cements Moscow’s new role as prime powerbroker in the Middle East as US influence in the region wanes.

2.25pm BST

Laura Cooper – the deputy assistant secretary of defense for Russia, Ukraine and Eurasia – has arrived to testify in House Democrats’ impeachment inquiry.

Cooper may be able to shed more light on the delaying of military aid to Ukraine, but her appearance feels a bit anticlimactic after Bill Taylor testified yesterday that he was told Trump specifically wanted a public announcement of investigations into Joe Biden and the 2016 election before releasing the aid.

Laura Cooper’s testimony for House Democrats underway after protest delayed her appearance by more than five hours

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1.37am BST

Here’s a recap of this evening’s developments:

12.56am BST

Trump and his supporters have said that there couldn’t have been a quid pro quo because Ukrainians weren’t aware that aid was being witheld.

Neither he (Taylor) or any other witness has provided testimony that the Ukrainians were aware that military aid was being withheld. You can’t have a quid pro quo with no quo.” Congressman John Ratcliffe @foxandfriends Where is the Whistleblower? The Do Nothing Dems case is DEAD!

Word of the aid freeze had gotten to high-level Ukrainian officials by the first week in August, according to interviews and documents obtained by The New York Times.

The problem was not a bureaucratic snag, the Ukrainians were told then. To address it, they were advised, they should reach out to Mick Mulvaney, the acting White House chief of staff, according to the interviews and records.