Not Russia or Mexico.
In newer versions of the mod, Spain begins as Republican Spain, and after an event in Historical mode, a lot of cities turn Nationalist, leaving you (if you chose Azana) to fight them off.
There's no real way to "convince" the AI to send you units, but oil trades are still possible.
Russia's first shipment of weapons was .. canned milk I believe. I can't remember exactly the item, but it wasn't weapons. A huge let down, and their long waiting for sending actual weapons was a huge burden.
France was going to support them before they ever asked for help from Russia. England convinced them to stay "neutral" which was total BS.
"In July, 1936, José Giral, the prime minister of the Popular Front government in Spain, requested aid from France. The prime minister, Leon Blum, agreed to send aircraft and artillery. However, after coming under pressure from Stanley Baldwin and Anthony Eden in Britain, and more right-wing members of his own cabinet, he changed his mind.
Baldwin and Blum now called for all countries in Europe not to intervene in the Spanish Civil War. In September 1936 a Non-Intervention Agreement was drawn-up and signed by 27 countries including Germany, Britain, France, the Soviet Union and Italy.
Benito Mussolini continued to give aid to General Francisco Franco and his Nationalist forces and during the first three months of the Nonintervention Agreement sent 90 Italian aircraft and refitted the cruiser Canaris, the largest ship in the Nationalists' fleet.
On 28th November the Italian government signed a secret treaty with the Spanish Nationalists. In return for military aid, the Nationalist agreed to allow Italy to establish bases in Spain in the case of a conflict with France. Over the next three months Mussolini sent to Spain 130 aircraft, 2,500 tons of bombs, 500 cannons, 700 mortars, 12,000 machine-guns, 50 whippet tanks and 3,800 motor vehicles.
Adolf Hitler also continued to give aid to General Francisco Franco and his Nationalist forces but attempted to disguise this by sending the men, planes, tanks, and munitions via Portugal. He also gave permission for the formation of the Condor Legion. The initial force consisted a Bomber Group of three squadrons of Ju-52 bombers; a Fighter Group with three squadrons of He-51 fighters; a Reconnaissance Group with two squadrons of He-99 and He-70 reconnaissance bombers; and a Seaplane Squadron of He-59 and He-60 floatplanes.
The Condor Legion, under the command of General Hugo Sperrle, was an autonomous unit responsible only to Franco. The legion would eventually total nearly 12,000 men. Sperrle demanded higher performance aircraft from Germany and he eventually received the Heinkel He111, Junkers Stuka and the Messerschmitt Bf109. It participated in all the major engagements including Brunete, Teruel, Aragon and Ebro.
The Communist Party, that had originally supported the Popular Front government in France, now organized demonstrations against Blum's policy of non-intervention. With the left-wing in open revolt against the government and a growing economic crisis, Blum decided to resign on 22nd June.
Maurice Thorez, the leader of the Communist Party in France, began to arrange the recruitment of soldiers to fight in the International Brigades for the Popular Front in Spain. The first group of volunteers left Toulouse on 29th July. The main recruitment centre was in Paris and from there they travelled by train to Perpignan. After spending the night in the town they were driven in trucks into Spain. Others went by sea via Marseilles.
The French supplied more men to fight with the Republican Army than any other country. Over 9,000 served, of whom some 3,000 were killed. It has been estimated that around half of all those who went were members of the Communist Party. The most prominent volunteer was André Malraux who organized a Republican air squadron."
Interestingly enough, I have about 10 books/pamplets on the spanish civil war next to me. Just got a book shipment in for my reading lists. Durruti is behind me on my shelf by Abel Paz.