Liberalism is the ideology of French revolution and similar revolutions around that time. It is basically the status quo of the current politics in the large parts of the world. Ideology of free markets, free speech, free assembly, etc (limitations may apply). It is ideology of capitalists/capitalism itself, they became the ruling class after dismantling the old aristocracies. In this time they try their hardest to keep the power and property they have accumulated and will try their best to uphold the current system. They are also the original leftists, because they sat to the left of the king in the general assembly in French parliament. And for their time they were a progressive force that dismantled feudalism. Currently they are basically center as I mentioned. Large parts of Democrat and Republican parties are liberals (the parts of republicans that want to bring a theocracy or ethnostate or something around aren't).