Why did it take until 1920 for women to have the right to vote?

The right to vote is basically part of the very definition of a functioning democracy. <br><br>The US was founded in 1776 but it took until 1920 for women to have the right to vote. That is well over a 100 year delay.<br><br>It makes sense that the founding fathers would have excluded women from voting, but I don't see why we didn't update our laws to reflect this much later.<br><br>What events and cultural attitudes caused this lag and how did they change over time? Did some women make the case for women having the right to vote in the 18th and 19th centuries in the US?