The 17th Amendment deprives the states of the right to appoint their own Senators to this position, thereby compromising the states' right to have a say in the affairs of the states. The idea was to separate power in Congress so as to have balance in the sensitive area of making laws and protecting the rights of the states themselves.
A body politic known as the House of Representatives would be proportioned to the people's voice. The Senate would however, be filled by trusted confidants and appointed by the duly elected representatives of each state's legislature. This would prevent them from being politicians and therefore their loyalty would remain with the concerns of the states' land, water and air and interactions with other states, etc.
This was done to protect the vote of the states from being compromised politically. The Senate is NOT supposed to be filled with politicians, but trusted employees of the state instead, as a check to runaway political power by Congress as a whole. Checks and balances.
The election of senators by the states reassured Anti-federalists that there would be some protection against the swallowing up of states and their powers by the federal government, providing a check on the power of the federal government. (Wikipedia)
The 41 states to ratify the 17th Amendment have voluntarily given up their right to be represented in the Senate but;
Utah - rejected on February. 26th, 1913
Delaware - rejected on March 18, 1913
Further the following states have to date taken no action;
These states have not given their consent to removal of their suffrage and are protected by Article V, wherein again;
that no State, without its Consent, shall be deprived of its equal Suffrage in the Senate."