Shaikh AbdurRahman ibn Nasir AS-Sa'di, one of Imam of Ahle Sunnat of our times, wrote in his Tafsir Surah Hud, 91:

"Based upon this, if the Muslims who live under Wilayah (rule) of disbelievers, if they strive and act upon making this Wilayah (rule) democratic (Jumhooriyah), in which the individuals and people have the rights to practice their religious and worldly rights, this would be better than to submit to a country which will oppress the religious and worldly rights, and which is desirous to annihilate them and make them their agents and servants"

Shaykh Ahmad Muhammad Shakir wrote in his epistle “Al-Kitab wa Sunnah yajibu ai Yakuna Masdar Al-Qawaneen fi Misr”:

“So we will have this way towards what we desire from support of the Sharee’ah, a constitutional and peaceful way: That we present our call to the community, and we exert efforts in it and openly announce it, then we should jump into the elections, and we refer it to the community, and if we fail once we will succeed many times, rather we will make our defeat, if we are defeated on the first time, as a prelude to our victory, which will stimulate our zeal, which will provoke our determination, that it will bring insight in the places of our steps, and that our actions are sincerely for Allah and in His way. And if the community approves us and is satisfied with our call and chooses to rule by our Shar’eeah, in obedience to His Lord, and they send our members to the parliament, we will have the way and for you to be satisfied and you be satisfied to what the constitution necessitates,  so you confer to us the keys of the ruling as all parties do when one of them wins the elections, and then we will confer, insha Allah, to what we promised, to male the laws based on the Book and the Sunnah. And from the signs of victory and announcement of success insha Allah, is that we see many people of intellect saying according to our view, and they desire to answer to our call, and that our community returns to its religions and Sharee’ah, and some strong Jam’iyat made this aim among their main aims”

Hafiz Thanaullah Madni on voting in elections: He wrote in his "Fatawa Thaniyah Madniyah" v 1 p 634 about voting in Pakistan:

"Considering Religious benefits, we consider it appropriate to vote for the party or the person which is closer and more sympathetic to Islam"

He wrote on p 636: ""When there is a religious person or someone who likes Islam against someone far from Religion or secular, then not voting at this time is not only wasting vote but indirectly giving advantage to people far away from religion"

About entering parliament, he allowed it on p 634 : "To participate in an Kafir or unjust system or to do Ta'awun, there is no difference between the two. The real aim is to do good and opportunities to reach it. In Islam Wasail follow Maqasid"