First try: TopoJSON on CartoDB

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <title>U.S. States</title>
    <script src="https://d3js.org/d3.v3.min.js"></script>
    <script src="https://d3js.org/d3.geo.projection.v0.min.js"></script>
    <script src="https://d3js.org/topojson.v0.min.js"></script>
    <script src="https://libs.cartocdn.com/cartodb.js/v2/cartodb.js"></script>
    <style type="text/css">

body{
        background:white;
    }
    svg {
      width: 960px;
      height: 500px;
      background: none;
    }
    svg:active {
      cursor: move;
      cursor: -moz-grabbing;
      cursor: -webkit-grabbing;
    }
    .globe {
      fill: black;
      fill-opacity: 1;
      stroke: #111;
      stroke-width:1px;
    }
    #first_layer path {
      stroke: #333;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
    </style>
  </head>
  <body>
    <script type="text/javascript">

var first_layer = 'd3_world_borders';

//var sql = new cartodb.SQL({ user: 'viz2', format: 'geojson', dp: 5});

// Define our SVG element outside our SQL functions
    var svg = d3.select("body")
            .append("svg")
            .call(d3.behavior.zoom()
                .on("zoom", redraw))
            .append("g");

var fill = d3.scale.linear()
        .domain([0, 1000, 10000000, 100000000, 1000000000])
        .range(["#fdfdfd", "#6ab9fa", "#39a2f8", "#098bf5", "#0666b4"]);

// Our projection.
    var xy = d3.geo.mercator()
              .scale(2000)
              .center([40,30]);

var path = d3.geo.path()
                .projection(xy)

svg.append("g").attr("id", "first_layer");

//sql.execute("SELECT ST_Simplify(the_geom,0.01) as the_geom, pop2005 as population FROM {{table_name}} WHERE the_geom IS NOT NULL", {table_name: first_layer})

d3.json("https://staging20.cartodb.com/api/v2/sql?q=SELECT the_geom, pop2005 as population FROM topojson_wb WHERE the_geom IS NOT NULL&format=topojson&dp=5", function(collection) {
      //var subunits = topojson.object(collection);
      var tj = {countries: {type: "GeometryCollection", geometries: []}};
      for (i in collection.objects){
        tj.countries.geometries.push(collection.objects[i])
      }
      collection.objects = tj
      
      svg.select("#first_layer")
        .selectAll("path")
          .data(topojson.object(collection, collection.objects.countries).geometries)
        .enter().append("path")
        .attr("fill", function(d) { return fill(d.properties.population); })
        .attr("stroke-width", "0.5px")
        .attr("fill-opacity", "0.7")
        .attr("d", path.projection(xy));
            });

function redraw() {
      svg.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")");
    }

</script>
  </body>
</html>

Modified http://d3js.org/d3.v3.min.js to a secure url

Modified http://d3js.org/d3.geo.projection.v0.min.js to a secure url

Modified http://d3js.org/topojson.v0.min.js to a secure url

Modified http://libs.cartocdn.com/cartodb.js/v2/cartodb.js to a secure url

https://d3js.org/d3.v3.min.js

https://d3js.org/d3.geo.projection.v0.min.js

https://d3js.org/topojson.v0.min.js

https://libs.cartocdn.com/cartodb.js/v2/cartodb.js