Why do political parties sign "agreements" with other foreign political parties?

Question

In this news article, it is mentioned that the Freedom Party of Austria has signed a "partnership agreement" with the United Russia Party of the Russian Federation:

The Freedom Party ... has longstanding ties to Russia. Strache signed a partnership agreement with Putin’s United Russia party in 2016.

This is not uncommon.

In August 2008, India's oldest political party - the Indian National Congress - has also signed a "Memorandum of Understanding" with the Chinese Communist Party (CCP) of the People's Republic of China.

In both cases, this wasn't an agreement between foreign governments, but a party-to-party agreement. Often, these agreements aren't made public (similar to some foreign government contracts).

My question is why do foreign political parties need to sign such agreements between themselves, that may or may not involve consultation with their own government, and what are these "agreements" about?

(Note that I do not attribute any malice, or accusations of indulging in "anti-national" activities to these acts. But I am interested to know about the motivations, and the international history, if any, behind such political actions.)

Answer 1

You might compare this with the concept of Track 1, Track 1.5, and Track 2 negotiations. When governments talk to each other, it is Track 1 and highly official. Academics and civil society are Track 2 and not official. Parties with government ties could be seen as something like Track 1.5.

In the european-union, there are different political parties in each country which organize themselves into groupings in the European Parliament, e.g. the EPP on the center-right, the PES on the center-left, ALDE for european-style liberalism, or the EGP for the Greens. The individual members of these groupings are quite diverse; just consider how long it took the EPP to throw out Fidesz.

Similar groupings and associations exist beyond the borders of the EU. PES membership overlaps with the Socialist International, and EPP membership overlaps with the Centrist Democrat International.

In many countries there is the political tradition to keep domestic politics inside and to stand together on the international stage. This is crumbling in the EU, where, say, German conservatives might make common cause with Austrian conservatives against the German socialists, and not see that as unpatriotic or illegitimate.

Another example from German history has a more antagonistic situation. After WWII, Germany was split into four occupation zones for the Soviets, US, UK, and France, and eastern areas seized by the Soviets and Poland. The three occupation zones in the West became the Federal German Republic (FRG) and the occupation zone in the East became the German Democratic Republic (GDR). The FRG always insisted that this division was just temporary, and in the meantime it pressured third parties to accept only the FRG as representative of Germany (the Hallstein doctrine). The two Germanies wanted to talk on practical and humanitarian issues, yet the FRG never admitted that their diplomats in East Berlin could be an embassy with an ambassador -- it had to be a mere permanent representation.

In the years before the permanent representation, when the FRG government tiptoed around anything resembling a recognition of the GDR, it was possible to have talks and letters between the Western SPD party and the Eastern SED party. These were understood to be somewhat substantial -- both parties played key roles in the respective states -- yet formally not state-to-state talks.

There are other countries, often authoritarian ones, where international cooperation gets labelled as foreign agents and suppressed.

And other cases where foreign parties are supported not because of a common ideology, but to destabilize another country.

Answer 2

Coordinating policy
As it has been already pointed out in the other answer, this makes a lot of sense on the scale of the European union, where the parties partially share common playing field - both in the European parliament, but also in terms of influencing their government policy, which ultimately influences the European one.

To a lesser extent this is also true when speaking about Russian and western parties - Russia benefits from such alliances, because they either distabilize western governments or make them shift to the right and adopt more conciliatory policies vis-à-vis Russia. European parties usually benefit financially, but also by getting an image of peacemakers/conciliators or simply by stressing their anti-establishment credentials. (This is unlike the Soviet support for various Communist and Socialist parties during the Soviet time, though perhaps with less ideological reasons, and less direct control from the side of Russia.)

Communist International
The idea of coordinated policy is not new. A well-known example is the successive Communist Internationals, which were unions of trade-unions, small political parties and some illegal groups from various countries, agreeing on the common policy, intended to eventually benefit all of them (until Stalin managed to completely subjugate all of them to the directives from Moscow.)

Secret pacts
The policy is not uncommon even on the state level. As an example, one could consider Sykes-Picot agreement and similar secret protocol to the Molotov-Ribbentrop pact. Perhaps the incredulity that arises about such agreements is fully expose here: if the agreement is secret, how can it be enforced? (Given that enforcing anything in international politics is already hard.) In my opinion, such agreements are mainly concluded in order to achieve mutual understanding ("the spheres of influence") and thus avoid unnecessary and expensive infighting. E.g., the secret protocol to the Molotov-Ribbentrop had to undergo several adjustments, to reflect the changing realities on the ground, where the Nazis occupied some areas intended for the USSR and vice versa.